diff --git a/packages/material-ui-lab/src/DesktopDatePicker/DesktopDatePicker.test.tsx b/packages/material-ui-lab/src/DesktopDatePicker/DesktopDatePicker.test.tsx
index 49d9a0eb40edbb..2ba8929dc61b52 100644
--- a/packages/material-ui-lab/src/DesktopDatePicker/DesktopDatePicker.test.tsx
+++ b/packages/material-ui-lab/src/DesktopDatePicker/DesktopDatePicker.test.tsx
@@ -86,6 +86,8 @@ describe('<DesktopDatePicker />', () => {
         TransitionComponent={FakeTransitionComponent}
         renderInput={(params) => <TextField {...params} />}
       />,
+      // TODO: React18Compat
+      { legacyRoot: true },
     );
 
     act(() => {
diff --git a/packages/material-ui-lab/src/DesktopDateTimePicker/DesktopDateTimePicker.test.tsx b/packages/material-ui-lab/src/DesktopDateTimePicker/DesktopDateTimePicker.test.tsx
index 8f56d6761dc37a..f329a52fce2e22 100644
--- a/packages/material-ui-lab/src/DesktopDateTimePicker/DesktopDateTimePicker.test.tsx
+++ b/packages/material-ui-lab/src/DesktopDateTimePicker/DesktopDateTimePicker.test.tsx
@@ -27,6 +27,8 @@ describe('<DesktopDateTimePicker />', () => {
         onChange={() => {}}
         renderInput={(params) => <TextField autoFocus {...params} />}
       />,
+      // TODO: React18Compat
+      { legacyRoot: true },
     );
 
     userEvent.mousePress(screen.getByLabelText(/choose date/i));
diff --git a/packages/material-ui-lab/src/TreeItem/TreeItem.test.js b/packages/material-ui-lab/src/TreeItem/TreeItem.test.js
index be855f13940fff..163e778da7d146 100644
--- a/packages/material-ui-lab/src/TreeItem/TreeItem.test.js
+++ b/packages/material-ui-lab/src/TreeItem/TreeItem.test.js
@@ -506,8 +506,8 @@ describe('<TreeItem />', () => {
 
           act(() => {
             screen.getByRole('tree').focus();
-            fireEvent.keyDown(screen.getByRole('tree'), { key: 'ArrowLeft' });
           });
+          fireEvent.keyDown(screen.getByRole('tree'), { key: 'ArrowLeft' });
 
           expect(firstItem).to.have.attribute('aria-expanded', 'false');
           expect(screen.getByTestId('one')).toHaveVirtualFocus();
@@ -1099,8 +1099,8 @@ describe('<TreeItem />', () => {
 
           act(() => {
             getByRole('tree').focus();
-            fireEvent.keyDown(getByRole('tree'), { key: ' ' });
           });
+          fireEvent.keyDown(getByRole('tree'), { key: ' ' });
 
           expect(getByTestId('one')).not.to.have.attribute('aria-selected');
         });
@@ -1440,16 +1440,16 @@ describe('<TreeItem />', () => {
             </TreeView>,
           );
 
+          fireEvent.click(getByText('five'));
+          fireEvent.click(getByText('five'));
           // Focus node five
           act(() => {
-            fireEvent.click(getByText('five'));
-            fireEvent.click(getByText('five'));
             getByRole('tree').focus();
-            fireEvent.keyDown(getByRole('tree'), {
-              key: 'End',
-              shiftKey: true,
-              ctrlKey: true,
-            });
+          });
+          fireEvent.keyDown(getByRole('tree'), {
+            key: 'End',
+            shiftKey: true,
+            ctrlKey: true,
           });
 
           expect(queryAllByRole('treeitem', { selected: true })).to.have.length(0);
diff --git a/packages/material-ui-lab/src/TreeView/TreeView.test.js b/packages/material-ui-lab/src/TreeView/TreeView.test.js
index d109c768dafaa2..129d8a281a4ca5 100644
--- a/packages/material-ui-lab/src/TreeView/TreeView.test.js
+++ b/packages/material-ui-lab/src/TreeView/TreeView.test.js
@@ -172,6 +172,8 @@ describe('<TreeView />', () => {
 
     act(() => {
       getByRole('tree').focus();
+    });
+    act(() => {
       getByRole('tree').blur();
     });
 
diff --git a/packages/material-ui-lab/src/internal/pickers/test-utils.tsx b/packages/material-ui-lab/src/internal/pickers/test-utils.tsx
index f9843fea36ce30..24f1fb401a258f 100644
--- a/packages/material-ui-lab/src/internal/pickers/test-utils.tsx
+++ b/packages/material-ui-lab/src/internal/pickers/test-utils.tsx
@@ -57,7 +57,10 @@ export function createPickerRender({
     );
   }
 
-  return (node: React.ReactElement) => clientRender(node, { wrapper: Wrapper });
+  return (
+    node: React.ReactElement,
+    options?: Omit<import('test/utils').RenderOptions, 'wrapper'>,
+  ) => clientRender(node, { ...options, wrapper: Wrapper });
 }
 
 export const queryByMuiTest = queryHelpers.queryByAttribute.bind(null, 'data-mui-test');
diff --git a/packages/material-ui-private-theming/src/ThemeProvider/ThemeProvider.test.js b/packages/material-ui-private-theming/src/ThemeProvider/ThemeProvider.test.js
index 459e8a3da3c7d4..e07bdc846f8891 100644
--- a/packages/material-ui-private-theming/src/ThemeProvider/ThemeProvider.test.js
+++ b/packages/material-ui-private-theming/src/ThemeProvider/ThemeProvider.test.js
@@ -1,6 +1,6 @@
 import * as React from 'react';
 import { expect } from 'chai';
-import { createClientRender } from 'test/utils';
+import { createClientRender, RenderCounter } from 'test/utils';
 import useTheme from '../useTheme';
 import ThemeProvider from './ThemeProvider';
 
@@ -49,24 +49,20 @@ describe('ThemeProvider', () => {
   });
 
   it('should memoize the merged output', () => {
-    const themes = [];
-
     const ref = React.createRef();
+    const getRenderCountRef = React.createRef();
     const text = () => ref.current.textContent;
     function Test() {
       const theme = useTheme();
-      React.useEffect(() => {
-        themes.push(theme);
-      });
-
       return (
-        <span ref={ref}>
-          {theme.foo}
-          {theme.bar}
-        </span>
+        <RenderCounter ref={getRenderCountRef}>
+          <span ref={ref}>
+            {theme.foo}
+            {theme.bar}
+          </span>
+        </RenderCounter>
       );
     }
-    const MemoTest = React.memo(Test);
 
     const outerTheme = { bar: 'bar' };
     const innerTheme = { foo: 'foo' };
@@ -75,7 +71,7 @@ describe('ThemeProvider', () => {
       return (
         <ThemeProvider theme={outerTheme}>
           <ThemeProvider theme={innerTheme}>
-            <MemoTest />
+            <Test />
           </ThemeProvider>
         </ThemeProvider>
       );
@@ -85,7 +81,7 @@ describe('ThemeProvider', () => {
     expect(text()).to.equal('foobar');
     setProps({});
     expect(text()).to.equal('foobar');
-    expect(themes).to.have.length(1);
+    expect(getRenderCountRef.current()).to.equal(2);
   });
 
   describe('warnings', () => {
diff --git a/packages/material-ui-unstyled/src/Portal/Portal.test.js b/packages/material-ui-unstyled/src/Portal/Portal.test.js
index a3d79b6d755a7b..2a3c5fc8453fc4 100644
--- a/packages/material-ui-unstyled/src/Portal/Portal.test.js
+++ b/packages/material-ui-unstyled/src/Portal/Portal.test.js
@@ -180,9 +180,13 @@ describe('<Portal />', () => {
 
     function Test(props) {
       const { container } = props;
+      const containerRef = React.useRef();
 
       React.useEffect(() => {
-        updateFunction();
+        if (containerRef.current !== container) {
+          updateFunction();
+        }
+        containerRef.current = container;
       }, [container]);
 
       return (
diff --git a/packages/material-ui-unstyled/src/Unstable_TrapFocus/Unstable_TrapFocus.test.js b/packages/material-ui-unstyled/src/Unstable_TrapFocus/Unstable_TrapFocus.test.js
index c78a76cd24c2f0..96e6186d79f036 100644
--- a/packages/material-ui-unstyled/src/Unstable_TrapFocus/Unstable_TrapFocus.test.js
+++ b/packages/material-ui-unstyled/src/Unstable_TrapFocus/Unstable_TrapFocus.test.js
@@ -15,7 +15,9 @@ describe('<TrapFocus />', () => {
     initialFocus = document.createElement('button');
     initialFocus.tabIndex = 0;
     document.body.appendChild(initialFocus);
-    initialFocus.focus();
+    act(() => {
+      initialFocus.focus();
+    });
   });
 
   afterEach(() => {
@@ -29,11 +31,15 @@ describe('<TrapFocus />', () => {
           <input autoFocus data-testid="auto-focus" />
         </div>
       </TrapFocus>,
+      // TODO: https://github.com/reactwg/react-18/discussions/18#discussioncomment-893076
+      { strictEffects: false },
     );
 
     expect(getByTestId('auto-focus')).toHaveFocus();
 
-    initialFocus.focus();
+    act(() => {
+      initialFocus.focus();
+    });
     expect(getByTestId('root')).toHaveFocus();
   });
 
@@ -44,11 +50,15 @@ describe('<TrapFocus />', () => {
           <input autoFocus data-testid="auto-focus" />
         </div>
       </TrapFocus>,
+      // TODO: https://github.com/reactwg/react-18/discussions/18#discussioncomment-893076s
+      { strictEffects: false },
     );
 
     expect(getByTestId('auto-focus')).toHaveFocus();
 
-    initialFocus.focus();
+    act(() => {
+      initialFocus.focus();
+    });
 
     expect(initialFocus).toHaveFocus();
   });
@@ -112,7 +122,9 @@ describe('<TrapFocus />', () => {
     }
     const { setProps } = render(<Test />);
     const portaledTextbox = screen.getByTestId('portal-input');
-    portaledTextbox.focus();
+    act(() => {
+      portaledTextbox.focus();
+    });
 
     // sanity check
     expect(portaledTextbox).toHaveFocus();
@@ -178,7 +190,11 @@ describe('<TrapFocus />', () => {
         </div>
       );
     }
-    const { setProps } = render(<Test />);
+    const { setProps } = render(<Test />, {
+      // Strict Effects interferes with the premise of the test.
+      // It would trigger a focus restore (i.e. a blur event)
+      strictEffects: false,
+    });
 
     // same behavior, just referential equality changes
     setProps({ isEnabled: () => true });
@@ -201,12 +217,16 @@ describe('<TrapFocus />', () => {
     const { setProps, getByRole } = render(<Test />);
     expect(screen.getByTestId('root')).toHaveFocus();
 
-    getByRole('textbox').focus();
+    act(() => {
+      getByRole('textbox').focus();
+    });
     expect(getByRole('textbox')).not.toHaveFocus();
 
     setProps({ isEnabled: () => false });
 
-    getByRole('textbox').focus();
+    act(() => {
+      getByRole('textbox').focus();
+    });
     expect(getByRole('textbox')).toHaveFocus();
   });
 
@@ -293,7 +313,9 @@ describe('<TrapFocus />', () => {
       const { setProps } = render(<WithRemovableElement />);
 
       expect(screen.getByTestId('root')).toHaveFocus();
-      screen.getByTestId('hide-button').focus();
+      act(() => {
+        screen.getByTestId('hide-button').focus();
+      });
       expect(screen.getByTestId('hide-button')).toHaveFocus();
 
       setProps({ hideButton: true });
@@ -313,10 +335,14 @@ describe('<TrapFocus />', () => {
           </div>,
         );
 
-        clock.tick(500); // trigger an interval call
+        act(() => {
+          clock.tick(500); // trigger an interval call
+        });
         expect(initialFocus).toHaveFocus();
 
-        getByRole('textbox').focus(); // trigger a focus event
+        act(() => {
+          getByRole('textbox').focus();
+        });
         expect(getByRole('textbox')).toHaveFocus();
       });
 
@@ -334,15 +360,21 @@ describe('<TrapFocus />', () => {
 
         expect(initialFocus).toHaveFocus();
 
-        screen.getByTestId('outside-input').focus();
+        act(() => {
+          screen.getByTestId('outside-input').focus();
+        });
         expect(screen.getByTestId('outside-input')).toHaveFocus();
 
         // the trap activates
-        screen.getByTestId('focus-input').focus();
+        act(() => {
+          screen.getByTestId('focus-input').focus();
+        });
         expect(screen.getByTestId('focus-input')).toHaveFocus();
 
         // the trap prevent to escape
-        screen.getByTestId('outside-input').focus();
+        act(() => {
+          screen.getByTestId('outside-input').focus();
+        });
         expect(screen.getByTestId('root')).toHaveFocus();
       });
 
@@ -361,11 +393,15 @@ describe('<TrapFocus />', () => {
         const { setProps } = render(<Test />);
 
         // set the expected focus restore location
-        screen.getByTestId('outside-input').focus();
+        act(() => {
+          screen.getByTestId('outside-input').focus();
+        });
         expect(screen.getByTestId('outside-input')).toHaveFocus();
 
         // the trap activates
-        screen.getByTestId('root').focus();
+        act(() => {
+          screen.getByTestId('root').focus();
+        });
         expect(screen.getByTestId('root')).toHaveFocus();
 
         // restore the focus to the first element before triggering the trap
diff --git a/packages/material-ui-utils/src/useIsFocusVisible.test.js b/packages/material-ui-utils/src/useIsFocusVisible.test.js
index ea0b5663787344..d229969ebdd13f 100644
--- a/packages/material-ui-utils/src/useIsFocusVisible.test.js
+++ b/packages/material-ui-utils/src/useIsFocusVisible.test.js
@@ -2,6 +2,7 @@ import { expect } from 'chai';
 import * as React from 'react';
 import * as ReactDOM from 'react-dom';
 import {
+  act,
   createClientRender,
   focusVisible,
   simulatePointerDevice,
@@ -48,7 +49,7 @@ const SimpleButton = React.forwardRef(function SimpleButton(props, ref) {
   );
 });
 
-describe('focus-visible polyfill', () => {
+describe('useIsFocusVisible', () => {
   const render = createClientRender();
 
   before(() => {
@@ -99,7 +100,9 @@ describe('focus-visible polyfill', () => {
 
       expect(button.classList.contains('focus-visible')).to.equal(false);
 
-      button.focus();
+      act(() => {
+        button.focus();
+      });
 
       if (programmaticFocusTriggersFocusVisible()) {
         expect(button).to.have.class('focus-visible');
@@ -107,7 +110,9 @@ describe('focus-visible polyfill', () => {
         expect(button).not.to.have.class('focus-visible');
       }
 
-      button.blur();
+      act(() => {
+        button.blur();
+      });
       focusVisible(button);
 
       expect(button.classList.contains('focus-visible')).to.equal(true);
diff --git a/packages/material-ui/src/Autocomplete/Autocomplete.test.js b/packages/material-ui/src/Autocomplete/Autocomplete.test.js
index afd4e2aa3c2d6b..33944a1ea2cbe7 100644
--- a/packages/material-ui/src/Autocomplete/Autocomplete.test.js
+++ b/packages/material-ui/src/Autocomplete/Autocomplete.test.js
@@ -27,7 +27,8 @@ function checkHighlightIs(listbox, expected) {
 }
 
 describe('<Autocomplete />', () => {
-  const render = createClientRender();
+  // TODO: React18Compat
+  const render = createClientRender({ legacyRoot: true });
 
   describeConformanceV5(
     <Autocomplete options={[]} renderInput={(params) => <TextField {...params} />} />,
diff --git a/packages/material-ui/src/Breadcrumbs/Breadcrumbs.test.js b/packages/material-ui/src/Breadcrumbs/Breadcrumbs.test.js
index 7c736b83e919d6..dfa7131494cbc9 100644
--- a/packages/material-ui/src/Breadcrumbs/Breadcrumbs.test.js
+++ b/packages/material-ui/src/Breadcrumbs/Breadcrumbs.test.js
@@ -1,6 +1,6 @@
 import * as React from 'react';
 import { expect } from 'chai';
-import { describeConformanceV5, act, createClientRender, screen } from 'test/utils';
+import { act, describeConformanceV5, createClientRender, screen } from 'test/utils';
 import Breadcrumbs, { breadcrumbsClasses as classes } from '@material-ui/core/Breadcrumbs';
 
 describe('<Breadcrumbs />', () => {
diff --git a/packages/material-ui/src/Button/Button.test.js b/packages/material-ui/src/Button/Button.test.js
index a1650ec2d0b5d5..6fed3d2ece3767 100644
--- a/packages/material-ui/src/Button/Button.test.js
+++ b/packages/material-ui/src/Button/Button.test.js
@@ -321,8 +321,8 @@ describe('<Button />', () => {
     );
     const button = getByRole('button');
 
+    fireEvent.keyDown(document.body, { key: 'TAB' });
     act(() => {
-      fireEvent.keyDown(document.body, { key: 'TAB' });
       button.focus();
     });
 
diff --git a/packages/material-ui/src/ButtonBase/ButtonBase.test.js b/packages/material-ui/src/ButtonBase/ButtonBase.test.js
index 2976163e30fe8b..99719e475cf25b 100644
--- a/packages/material-ui/src/ButtonBase/ButtonBase.test.js
+++ b/packages/material-ui/src/ButtonBase/ButtonBase.test.js
@@ -234,7 +234,9 @@ describe('<ButtonBase />', () => {
       fireEvent.click(button);
       expect(onClick.callCount).to.equal(1);
 
-      button.focus();
+      act(() => {
+        button.focus();
+      });
       expect(onFocus.callCount).to.equal(1);
 
       fireEvent.keyDown(button);
@@ -243,7 +245,9 @@ describe('<ButtonBase />', () => {
       fireEvent.keyUp(button);
       expect(onKeyUp.callCount).to.equal(1);
 
-      button.blur();
+      act(() => {
+        button.blur();
+      });
       expect(onBlur.callCount).to.equal(1);
 
       fireEvent.mouseLeave(button);
@@ -775,7 +779,9 @@ describe('<ButtonBase />', () => {
 
       expect(button).not.to.have.class(classes.focusVisible);
 
-      button.focus();
+      act(() => {
+        button.focus();
+      });
 
       if (programmaticFocusTriggersFocusVisible()) {
         expect(button).to.have.class(classes.focusVisible);
diff --git a/packages/material-ui/src/Chip/Chip.test.js b/packages/material-ui/src/Chip/Chip.test.js
index f3feeccd4d2854..d0e7750d509e61 100644
--- a/packages/material-ui/src/Chip/Chip.test.js
+++ b/packages/material-ui/src/Chip/Chip.test.js
@@ -404,7 +404,10 @@ describe('<Chip />', () => {
         const handleKeyDown = spy();
         const { container } = render(<Chip label={<input />} onKeyDown={handleKeyDown} />);
         const input = container.querySelector('input');
-        input.focus();
+
+        act(() => {
+          input.focus();
+        });
         fireEvent.keyDown(input, { key: 'Backspace' });
 
         expect(handleKeyDown.callCount).to.equal(1);
@@ -553,7 +556,9 @@ describe('<Chip />', () => {
 
       expect(chip).not.to.have.class(classes.focusVisible);
 
-      chip.focus();
+      act(() => {
+        chip.focus();
+      });
 
       if (programmaticFocusTriggersFocusVisible()) {
         expect(chip).to.have.class(classes.focusVisible);
diff --git a/packages/material-ui/src/Collapse/Collapse.test.js b/packages/material-ui/src/Collapse/Collapse.test.js
index 2d1bee05b26d27..af09064f1ecca6 100644
--- a/packages/material-ui/src/Collapse/Collapse.test.js
+++ b/packages/material-ui/src/Collapse/Collapse.test.js
@@ -1,7 +1,7 @@
 import * as React from 'react';
 import { expect } from 'chai';
 import { spy, stub, useFakeTimers } from 'sinon';
-import { createClientRender, describeConformanceV5 } from 'test/utils';
+import { act, createClientRender, describeConformanceV5 } from 'test/utils';
 import { ThemeProvider, createTheme } from '@material-ui/core/styles';
 import { Transition } from 'react-transition-group';
 import Collapse, { collapseClasses as classes } from '@material-ui/core/Collapse';
@@ -109,7 +109,10 @@ describe('<Collapse />', () => {
       expect(handleEntering.callCount).to.equal(1);
       expect(handleEntering.args[0][0]).to.equal(collapse);
       expect(handleEntering.args[0][1]).to.equal(false);
-      clock.tick(300);
+      act(() => {
+        clock.tick(300);
+      });
+
       expect(handleEntered.args[0][0].style.height).to.equal('auto');
       expect(handleEntered.args[0][1]).to.equal(false);
       expect(handleEntered.callCount).to.equal(1);
@@ -118,13 +121,20 @@ describe('<Collapse />', () => {
     it('should run out', () => {
       setProps({ in: true });
       setProps({ in: false });
+
       expect(nodeExitHeightStyle).to.equal('666px');
       expect(handleExiting.args[0][0].style.height).to.equal('0px');
       expect(handleExiting.callCount).to.equal(1);
       expect(handleExiting.args[0][0]).to.equal(collapse);
-      clock.tick(300);
+      act(() => {
+        clock.tick(300);
+      });
+
       expect(handleExited.args[0][0].style.height).to.equal('0px');
-      clock.tick(300);
+      act(() => {
+        clock.tick(300);
+      });
+
       expect(handleExited.callCount).to.equal(1);
       expect(handleExited.args[0][0]).to.equal(collapse);
     });
@@ -167,9 +177,15 @@ describe('<Collapse />', () => {
 
       const autoTransitionDuration = 10;
       expect(next1.callCount).to.equal(0);
-      clock.tick(0);
+      act(() => {
+        clock.tick(0);
+      });
+
       expect(next1.callCount).to.equal(0);
-      clock.tick(autoTransitionDuration);
+      act(() => {
+        clock.tick(autoTransitionDuration);
+      });
+
       expect(next1.callCount).to.equal(1);
 
       const next2 = spy();
@@ -181,7 +197,10 @@ describe('<Collapse />', () => {
       renderProps2.setProps({ in: true });
 
       expect(next2.callCount).to.equal(0);
-      clock.tick(0);
+      act(() => {
+        clock.tick(0);
+      });
+
       expect(next2.callCount).to.equal(1);
     });
 
@@ -197,9 +216,15 @@ describe('<Collapse />', () => {
       setProps({ in: true });
 
       expect(next.callCount).to.equal(0);
-      clock.tick(0);
+      act(() => {
+        clock.tick(0);
+      });
+
       expect(next.callCount).to.equal(0);
-      clock.tick(timeout);
+      act(() => {
+        clock.tick(timeout);
+      });
+
       expect(next.callCount).to.equal(1);
     });
 
diff --git a/packages/material-ui/src/Fade/Fade.test.js b/packages/material-ui/src/Fade/Fade.test.js
index fbc7defaed1809..2307c6f556cdea 100644
--- a/packages/material-ui/src/Fade/Fade.test.js
+++ b/packages/material-ui/src/Fade/Fade.test.js
@@ -1,7 +1,7 @@
 import * as React from 'react';
 import { expect } from 'chai';
 import { spy, useFakeTimers } from 'sinon';
-import { createClientRender, describeConformance } from 'test/utils';
+import { act, createClientRender, describeConformance } from 'test/utils';
 import { Transition } from 'react-transition-group';
 import Fade from '@material-ui/core/Fade';
 
@@ -69,7 +69,10 @@ describe('<Fade />', () => {
       expect(handleEntering.callCount).to.equal(1);
       expect(handleEntering.args[0][0]).to.equal(child);
 
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
+
       expect(handleEntered.callCount).to.equal(1);
       expect(handleEntered.args[0][0]).to.equal(child);
 
@@ -85,7 +88,10 @@ describe('<Fade />', () => {
       expect(handleExiting.callCount).to.equal(1);
       expect(handleExiting.args[0][0]).to.equal(child);
 
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
+
       expect(handleExited.callCount).to.equal(1);
       expect(handleExited.args[0][0]).to.equal(child);
     });
diff --git a/packages/material-ui/src/FormControl/FormControl.test.js b/packages/material-ui/src/FormControl/FormControl.test.js
index 16edd3db34a8aa..b7e239935f74e6 100644
--- a/packages/material-ui/src/FormControl/FormControl.test.js
+++ b/packages/material-ui/src/FormControl/FormControl.test.js
@@ -96,10 +96,10 @@ describe('<FormControl />', () => {
       act(() => {
         container.querySelector('input').focus();
       });
-      expect(readContext.args[1][0]).to.have.property('focused', true);
+      expect(readContext.lastCall.args[0]).to.have.property('focused', true);
 
       setProps({ disabled: true });
-      expect(readContext.args[2][0]).to.have.property('focused', false);
+      expect(readContext.lastCall.args[0]).to.have.property('focused', false);
     });
   });
 
diff --git a/packages/material-ui/src/Grow/Grow.test.js b/packages/material-ui/src/Grow/Grow.test.js
index e632d0e5ba1d02..27b60fbb9719d4 100644
--- a/packages/material-ui/src/Grow/Grow.test.js
+++ b/packages/material-ui/src/Grow/Grow.test.js
@@ -76,7 +76,10 @@ describe('<Grow />', () => {
       expect(handleEntering.callCount).to.equal(1);
       expect(handleEntering.args[0][0]).to.equal(child);
 
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
+
       expect(handleEntered.callCount).to.equal(1);
       expect(handleEntered.args[0][0]).to.equal(child);
 
@@ -97,7 +100,10 @@ describe('<Grow />', () => {
       expect(handleExiting.callCount).to.equal(1);
       expect(handleExiting.args[0][0]).to.equal(child);
 
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
+
       expect(handleExited.callCount).to.equal(1);
       expect(handleExited.args[0][0]).to.equal(child);
     });
@@ -239,14 +245,19 @@ describe('<Grow />', () => {
           </Grow>,
         );
 
-        clock.tick(0);
+        act(() => {
+          clock.tick(0);
+        });
 
         setProps({
           in: false,
         });
 
         expect(handleExited.callCount).to.equal(0);
-        clock.tick(0);
+        act(() => {
+          clock.tick(0);
+        });
+
         expect(handleExited.callCount).to.equal(1);
       });
 
@@ -257,15 +268,23 @@ describe('<Grow />', () => {
           <Grow {...defaultProps} timeout={timeout} onExited={handleExited} />,
         );
 
-        clock.tick(timeout);
+        act(() => {
+          clock.tick(timeout);
+        });
         setProps({
           in: false,
         });
 
         expect(handleExited.callCount).to.equal(0);
-        clock.tick(0);
+        act(() => {
+          clock.tick(0);
+        });
+
         expect(handleExited.callCount).to.equal(0);
-        clock.tick(timeout);
+        act(() => {
+          clock.tick(timeout);
+        });
+
         expect(handleExited.callCount).to.equal(1);
       });
 
diff --git a/packages/material-ui/src/InputBase/InputBase.test.js b/packages/material-ui/src/InputBase/InputBase.test.js
index e51fc05c07c6e8..aeaf79eee9c036 100644
--- a/packages/material-ui/src/InputBase/InputBase.test.js
+++ b/packages/material-ui/src/InputBase/InputBase.test.js
@@ -250,6 +250,8 @@ describe('<InputBase />', () => {
         expect(() => {
           render(
             <InputBase inputProps={{ ref: triggerChangeRef }} inputComponent={BadInputComponent} />,
+            // StrictEffectsViolation: Need to assert twice the number of error messages
+            { strictEffects: false },
           );
         }).toErrorDev(
           [
@@ -479,9 +481,12 @@ describe('<InputBase />', () => {
               </div>
             </FormControl>,
           );
-        }).toErrorDev(
+        }).toErrorDev([
           'Material-UI: There are multiple `InputBase` components inside a FormControl.\nThis creates visual inconsistencies, only use one `InputBase`.',
-        );
+          // React 18 Strict Effects run mount effects twice
+          React.version.startsWith('18') &&
+            'Material-UI: There are multiple `InputBase` components inside a FormControl.\nThis creates visual inconsistencies, only use one `InputBase`.',
+        ]);
       });
 
       it('should not warn if only one input is rendered', () => {
diff --git a/packages/material-ui/src/ListItem/ListItem.test.js b/packages/material-ui/src/ListItem/ListItem.test.js
index d96aa725356407..ebb3bbbd194a7e 100644
--- a/packages/material-ui/src/ListItem/ListItem.test.js
+++ b/packages/material-ui/src/ListItem/ListItem.test.js
@@ -180,9 +180,12 @@ describe('<ListItem />', () => {
       it('should warn (but not error) with autoFocus with a function component with no content', () => {
         expect(() => {
           render(<ListItem component={NoContent} autoFocus />);
-        }).toErrorDev(
+        }).toErrorDev([
           'Material-UI: Unable to set focus to a ListItem whose component has not been rendered.',
-        );
+          // React 18 Strict Effects run mount effects twice
+          React.version.startsWith('18') &&
+            'Material-UI: Unable to set focus to a ListItem whose component has not been rendered.',
+        ]);
       });
     });
   });
diff --git a/packages/material-ui/src/Menu/Menu.test.js b/packages/material-ui/src/Menu/Menu.test.js
index cb2653dcb4a5a3..6a77f9c009950b 100644
--- a/packages/material-ui/src/Menu/Menu.test.js
+++ b/packages/material-ui/src/Menu/Menu.test.js
@@ -53,7 +53,10 @@ describe('<Menu />', () => {
           />,
         );
 
-        expect(handleEnter.callCount).to.equal(1);
+        expect(handleEnter.callCount).to.equal(
+          // onEnter is called on mount which is run twice with Strict Effects
+          React.version.startsWith('18') ? 2 : 1,
+        );
         expect(handleEnter.args[0].length).to.equal(2);
         expect(handleEntering.callCount).to.equal(1);
         expect(handleEntering.args[0].length).to.equal(2);
diff --git a/packages/material-ui/src/MenuItem/MenuItem.test.js b/packages/material-ui/src/MenuItem/MenuItem.test.js
index 3b5f4d96fbc63a..cbceac934bbd0b 100644
--- a/packages/material-ui/src/MenuItem/MenuItem.test.js
+++ b/packages/material-ui/src/MenuItem/MenuItem.test.js
@@ -1,7 +1,7 @@
 import * as React from 'react';
 import { expect } from 'chai';
 import { spy } from 'sinon';
-import { describeConformanceV5, createClientRender, fireEvent, screen } from 'test/utils';
+import { act, describeConformanceV5, createClientRender, fireEvent, screen } from 'test/utils';
 import MenuItem, { menuItemClasses as classes } from '@material-ui/core/MenuItem';
 import ButtonBase from '@material-ui/core/ButtonBase';
 import ListContext from '../List/ListContext';
@@ -84,7 +84,9 @@ describe('<MenuItem />', () => {
       );
       const menuitem = screen.getByRole('menuitem');
 
-      menuitem.focus();
+      act(() => {
+        menuitem.focus();
+      });
 
       expect(handleFocus.callCount).to.equal(1);
 
diff --git a/packages/material-ui/src/Modal/Modal.test.js b/packages/material-ui/src/Modal/Modal.test.js
index 17cda4c1ac19c9..a2b006832ca82d 100644
--- a/packages/material-ui/src/Modal/Modal.test.js
+++ b/packages/material-ui/src/Modal/Modal.test.js
@@ -237,27 +237,6 @@ describe('<Modal />', () => {
 
       expect(onBackdropClick).to.have.property('callCount', 0);
     });
-
-    // Test case for https://github.com/mui-org/material-ui/issues/12831
-    it('should unmount the children when starting open and closing immediately', () => {
-      function TestCase() {
-        const [open, setOpen] = React.useState(true);
-
-        React.useEffect(() => {
-          setOpen(false);
-        }, []);
-
-        return (
-          <Modal open={open}>
-            <Fade in={open}>
-              <div id="modal-body">hello</div>
-            </Fade>
-          </Modal>
-        );
-      }
-      render(<TestCase />);
-      expect(document.querySelector('#modal-body')).to.equal(null);
-    });
   });
 
   describe('hide backdrop', () => {
@@ -283,7 +262,9 @@ describe('<Modal />', () => {
           <div data-testid="modal" tabIndex={-1} />
         </Modal>,
       );
-      getByTestId('modal').focus();
+      act(() => {
+        getByTestId('modal').focus();
+      });
 
       fireEvent.keyDown(getByTestId('modal'), {
         key: 'j', // Not escape
@@ -302,7 +283,9 @@ describe('<Modal />', () => {
           </Modal>
         </div>,
       );
-      getByTestId('modal').focus();
+      act(() => {
+        getByTestId('modal').focus();
+      });
 
       fireEvent.keyDown(getByTestId('modal'), {
         key: 'Escape',
@@ -322,7 +305,9 @@ describe('<Modal />', () => {
           </Modal>
         </div>,
       );
-      getByTestId('modal').focus();
+      act(() => {
+        getByTestId('modal').focus();
+      });
 
       fireEvent.keyDown(getByTestId('modal'), {
         key: 'Escape',
@@ -423,7 +408,9 @@ describe('<Modal />', () => {
       initialFocus = document.createElement('button');
       initialFocus.tabIndex = 0;
       document.body.appendChild(initialFocus);
-      initialFocus.focus();
+      act(() => {
+        initialFocus.focus();
+      });
     });
 
     afterEach(() => {
@@ -451,6 +438,8 @@ describe('<Modal />', () => {
             <input data-testid="auto-focus" type="text" autoFocus />
           </div>
         </Modal>,
+        // TODO: https://github.com/reactwg/react-18/discussions/18#discussioncomment-893076
+        { strictEffects: false },
       );
 
       expect(getByTestId('auto-focus')).toHaveFocus();
@@ -551,12 +540,40 @@ describe('<Modal />', () => {
 
         act(() => {
           getByTestId('foreign-input').focus();
+        });
+        act(() => {
           // wait for the `contain` interval check to kick in.
           clock.tick(500);
         });
 
         expect(getByTestId('foreign-input')).toHaveFocus();
       });
+
+      // Test case for https://github.com/mui-org/material-ui/issues/12831
+      it('should unmount the children when starting open and closing immediately', () => {
+        const timeout = 50;
+        function TestCase() {
+          const [open, setOpen] = React.useState(true);
+
+          React.useEffect(() => {
+            setOpen(false);
+          }, []);
+
+          return (
+            <Modal open={open}>
+              <Fade in={open} timeout={timeout}>
+                <div id="modal-body">hello</div>
+              </Fade>
+            </Modal>
+          );
+        }
+        render(<TestCase />);
+        // exit transition started
+        act(() => {
+          clock.tick(timeout);
+        });
+        expect(document.querySelector('#modal-body')).to.equal(null);
+      });
     });
   });
 
diff --git a/packages/material-ui/src/Popover/Popover.test.js b/packages/material-ui/src/Popover/Popover.test.js
index 328894fe1db9b1..531dbb78d84046 100644
--- a/packages/material-ui/src/Popover/Popover.test.js
+++ b/packages/material-ui/src/Popover/Popover.test.js
@@ -188,7 +188,10 @@ describe('<Popover />', () => {
         </Popover>,
       );
 
-      expect(handleEnter.callCount).to.equal(1);
+      expect(handleEnter.callCount).to.equal(
+        // onEnter is called on mount which is run twice with Strict Effects
+        React.version.startsWith('18') ? 2 : 1,
+      );
     });
 
     it('should fire Popover transition event callbacks', () => {
@@ -225,7 +228,8 @@ describe('<Popover />', () => {
         onExited: handleExited.callCount,
         onExiting: handleExiting.callCount,
       }).to.deep.equal({
-        onEnter: 1,
+        // onEnter is called on mount which is run twice with Strict Effects
+        onEnter: React.version.startsWith('18') ? 2 : 1,
         onEntering: 1,
         onEntered: 0,
         onExit: 0,
@@ -245,7 +249,8 @@ describe('<Popover />', () => {
         onExited: handleExited.callCount,
         onExiting: handleExiting.callCount,
       }).to.deep.equal({
-        onEnter: 1,
+        // onEnter is called on mount which is run twice with Strict Effects
+        onEnter: React.version.startsWith('18') ? 2 : 1,
         onEntering: 1,
         onEntered: 1,
         onExit: 0,
@@ -263,7 +268,8 @@ describe('<Popover />', () => {
         onExited: handleExited.callCount,
         onExiting: handleExiting.callCount,
       }).to.deep.equal({
-        onEnter: 1,
+        // onEnter is called on mount which is run twice with Strict Effects
+        onEnter: React.version.startsWith('18') ? 2 : 1,
         onEntering: 1,
         onEntered: 1,
         onExit: 1,
@@ -283,7 +289,8 @@ describe('<Popover />', () => {
         onExited: handleExited.callCount,
         onExiting: handleExiting.callCount,
       }).to.deep.equal({
-        onEnter: 1,
+        // onEnter is called on mount which is run twice with Strict Effects
+        onEnter: React.version.startsWith('18') ? 2 : 1,
         onEntering: 1,
         onEntered: 1,
         onExit: 1,
diff --git a/packages/material-ui/src/Popper/Popper.test.js b/packages/material-ui/src/Popper/Popper.test.js
index 4a545784b8b89d..969f7803bbf222 100644
--- a/packages/material-ui/src/Popper/Popper.test.js
+++ b/packages/material-ui/src/Popper/Popper.test.js
@@ -9,7 +9,10 @@ import Popper from '@material-ui/core/Popper';
 
 describe('<Popper />', () => {
   let rtlTheme;
-  const render = createClientRender();
+  const render = createClientRender({
+    // StrictEffectsViolation: need to call `handleOpen` in mount effects
+    strictEffects: false,
+  });
   const defaultProps = {
     anchorEl: () => document.createElement('svg'),
     children: <span>Hello World</span>,
diff --git a/packages/material-ui/src/RadioGroup/RadioGroup.test.js b/packages/material-ui/src/RadioGroup/RadioGroup.test.js
index 14f4254353359b..222b7db1b2b8f8 100644
--- a/packages/material-ui/src/RadioGroup/RadioGroup.test.js
+++ b/packages/material-ui/src/RadioGroup/RadioGroup.test.js
@@ -184,7 +184,9 @@ describe('<RadioGroup />', () => {
       const actionsRef = React.createRef();
       render(<RadioGroup actions={actionsRef} value="" />);
 
-      actionsRef.current.focus();
+      act(() => {
+        actionsRef.current.focus();
+      });
     });
   });
 
diff --git a/packages/material-ui/src/Select/Select.test.js b/packages/material-ui/src/Select/Select.test.js
index 168cd5b7d541f0..2bafe97f575a14 100644
--- a/packages/material-ui/src/Select/Select.test.js
+++ b/packages/material-ui/src/Select/Select.test.js
@@ -380,7 +380,9 @@ describe('<Select />', () => {
           ),
         ).toWarnDev([
           'Material-UI: You have provided an out-of-range value `20` for the select component.',
-          // strict mode renders twice
+          // React 18 Strict Effects run mount effects twice
+          React.version.startsWith('18') &&
+            'Material-UI: You have provided an out-of-range value `20` for the select component.',
           'Material-UI: You have provided an out-of-range value `20` for the select component.',
         ]);
       });
@@ -459,7 +461,9 @@ describe('<Select />', () => {
     specify('the listbox is focusable', () => {
       const { getByRole } = render(<Select open value="" />);
 
-      getByRole('listbox').focus();
+      act(() => {
+        getByRole('listbox').focus();
+      });
 
       expect(getByRole('listbox')).toHaveFocus();
     });
@@ -694,7 +698,9 @@ describe('<Select />', () => {
       }
       const { container, getByRole } = render(<ControlledWrapper />);
       const openSelect = container.querySelector('#open-select');
-      openSelect.focus();
+      act(() => {
+        openSelect.focus();
+      });
       fireEvent.click(openSelect);
 
       const option = getByRole('option');
@@ -856,6 +862,10 @@ describe('<Select />', () => {
 
     describe('errors', () => {
       it('should throw if non array', function test() {
+        // FIXME: leaks into subsequent tests due to https://github.com/facebook/react/issues/21765
+        if (React.version.startsWith('18')) {
+          this.skip();
+        }
         // TODO is this fixed?
         if (!/jsdom/.test(window.navigator.userAgent)) {
           // can't catch render errors in the browser for unknown reason
@@ -876,6 +886,8 @@ describe('<Select />', () => {
           );
         }).toErrorDev([
           'Material-UI: The `value` prop must be an array',
+          // React 18 Strict Effects run mount effects twice
+          React.version.startsWith('18') && 'Material-UI: The `value` prop must be an array',
           'The above error occurred in the <ForwardRef(SelectInput)> component',
         ]);
         const {
diff --git a/packages/material-ui/src/Slide/Slide.test.js b/packages/material-ui/src/Slide/Slide.test.js
index a85e3e9b9b23e3..24954bcb856746 100644
--- a/packages/material-ui/src/Slide/Slide.test.js
+++ b/packages/material-ui/src/Slide/Slide.test.js
@@ -1,7 +1,7 @@
 import * as React from 'react';
 import { expect } from 'chai';
 import { spy, stub, useFakeTimers } from 'sinon';
-import { createClientRender, describeConformance } from 'test/utils';
+import { act, createClientRender, describeConformance } from 'test/utils';
 import { createTheme } from '@material-ui/core/styles';
 import { Transition } from 'react-transition-group';
 import Slide from '@material-ui/core/Slide';
@@ -98,7 +98,9 @@ describe('<Slide />', () => {
       expect(handleEntering.callCount).to.equal(1);
       expect(handleEntering.args[0][0]).to.equal(child);
 
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
       expect(handleEntered.callCount).to.equal(1);
 
       setProps({ in: false });
@@ -109,7 +111,9 @@ describe('<Slide />', () => {
       expect(handleExiting.callCount).to.equal(1);
       expect(handleExiting.args[0][0]).to.equal(child);
 
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
       expect(handleExited.callCount).to.equal(1);
       expect(handleExited.args[0][0]).to.equal(child);
     });
@@ -490,10 +494,12 @@ describe('<Slide />', () => {
         </Slide>,
       );
 
-      window.dispatchEvent(new window.Event('resize', {}));
-      clock.tick(166);
-      const child = container.querySelector('#testChild');
+      act(() => {
+        window.dispatchEvent(new window.Event('resize', {}));
+        clock.tick(166);
+      });
 
+      const child = container.querySelector('#testChild');
       expect(child.style.transform).not.to.equal(undefined);
     });
 
@@ -518,8 +524,10 @@ describe('<Slide />', () => {
 
     it('should do nothing when visible', () => {
       render(<Slide {...defaultProps} />);
-      window.dispatchEvent(new window.Event('resize', {}));
-      clock.tick(166);
+      act(() => {
+        window.dispatchEvent(new window.Event('resize', {}));
+        clock.tick(166);
+      });
     });
   });
 
diff --git a/packages/material-ui/src/Slider/Slider.test.js b/packages/material-ui/src/Slider/Slider.test.js
index 8f64e471fd3508..f00ba1f365d73e 100644
--- a/packages/material-ui/src/Slider/Slider.test.js
+++ b/packages/material-ui/src/Slider/Slider.test.js
@@ -67,7 +67,9 @@ describe('<Slider />', () => {
     expect(handleChangeCommitted.callCount).to.equal(1);
     expect(handleChangeCommitted.args[0][1]).to.equal(10);
 
-    slider.focus();
+    act(() => {
+      slider.focus();
+    });
     fireEvent.change(slider, { target: { value: 23 } });
     expect(handleChange.callCount).to.equal(2);
     expect(handleChangeCommitted.callCount).to.equal(2);
@@ -172,8 +174,8 @@ describe('<Slider />', () => {
 
       act(() => {
         slider1.focus();
-        fireEvent.change(slider1, { target: { value: '21' } });
       });
+      fireEvent.change(slider1, { target: { value: '21' } });
 
       expect(slider1.getAttribute('aria-valuenow')).to.equal('21');
       expect(slider2.getAttribute('aria-valuenow')).to.equal('30');
@@ -188,8 +190,8 @@ describe('<Slider />', () => {
 
       act(() => {
         slider1.focus();
-        fireEvent.change(slider1, { target: { value: '31' } });
       });
+      fireEvent.change(slider1, { target: { value: '31' } });
 
       expect(slider1.getAttribute('aria-valuenow')).to.equal('31');
       expect(slider2.getAttribute('aria-valuenow')).to.equal('31');
@@ -197,8 +199,8 @@ describe('<Slider />', () => {
 
       act(() => {
         slider1.focus();
-        fireEvent.change(slider1, { target: { value: '32' } });
       });
+      fireEvent.change(slider1, { target: { value: '32' } });
 
       expect(slider1.getAttribute('aria-valuenow')).to.equal('31');
       expect(slider2.getAttribute('aria-valuenow')).to.equal('32');
@@ -959,11 +961,11 @@ describe('<Slider />', () => {
 
     act(() => {
       slider.focus();
-      fireEvent.change(slider, {
-        target: {
-          value: 4,
-        },
-      });
+    });
+    fireEvent.change(slider, {
+      target: {
+        value: 4,
+      },
     });
 
     expect(handleChange.callCount).to.equal(1);
@@ -1129,8 +1131,8 @@ describe('<Slider />', () => {
 
       act(() => {
         slider1.focus();
-        fireEvent.change(slider2, { target: { value: '19' } });
       });
+      fireEvent.change(slider2, { target: { value: '19' } });
       expect(handleChange.args[0][1]).to.deep.equal([20, 20]);
       expect(document.activeElement).to.have.attribute('data-index', '1');
     });
diff --git a/packages/material-ui/src/Snackbar/Snackbar.test.js b/packages/material-ui/src/Snackbar/Snackbar.test.js
index 712758056f55fc..d2c456f0f398fc 100644
--- a/packages/material-ui/src/Snackbar/Snackbar.test.js
+++ b/packages/material-ui/src/Snackbar/Snackbar.test.js
@@ -65,62 +65,82 @@ describe('<Snackbar />', () => {
   describe('Consecutive messages', () => {
     it('should support synchronous onExited callback', () => {
       const messageCount = 2;
-      let view;
-      const handleCloseSpy = spy();
-      const handleClose = () => {
-        view.setProps({ open: false });
-        handleCloseSpy();
-      };
-      const handleExitedSpy = spy();
-      const handleExited = () => {
-        handleExitedSpy();
-        if (handleExitedSpy.callCount < messageCount) {
-          view.setProps({ open: true });
-        }
-      };
+
+      const onClose = spy();
+      const onExited = spy();
       const duration = 250;
-      view = render(
-        <Snackbar
-          open={false}
-          onClose={handleClose}
-          TransitionProps={{ onExited: handleExited }}
+
+      let setSnackbarOpen;
+      function Test() {
+        const [open, setOpen] = React.useState(false);
+        setSnackbarOpen = setOpen;
+
+        function handleClose() {
+          setOpen(false);
+          onClose();
+        }
+
+        function handleExited() {
+          onExited();
+          if (onExited.callCount < messageCount) {
+            setOpen(true);
+          }
+        }
+
+        return (
+          <Snackbar
+            open={open}
+            onClose={handleClose}
+            TransitionProps={{ onExited: handleExited }}
+            message="message"
+            autoHideDuration={duration}
+            transitionDuration={duration / 2}
+          />
+        );
+      }
+      render(
+        <Test
+          onClose={onClose}
+          onExited={onExited}
           message="message"
           autoHideDuration={duration}
           transitionDuration={duration / 2}
         />,
       );
 
-      expect(handleCloseSpy.callCount).to.equal(0);
-      expect(handleExitedSpy.callCount).to.equal(0);
+      expect(onClose.callCount).to.equal(0);
+      expect(onExited.callCount).to.equal(0);
 
-      view.setProps({ open: true });
+      act(() => {
+        setSnackbarOpen(true);
+      });
       act(() => {
         clock.tick(duration);
       });
 
-      expect(handleCloseSpy.callCount).to.equal(1);
-      expect(handleExitedSpy.callCount).to.equal(0);
+      expect(onClose.callCount).to.equal(1);
+      expect(onExited.callCount).to.equal(0);
 
       act(() => {
         clock.tick(duration / 2);
       });
 
-      expect(handleCloseSpy.callCount).to.equal(1);
-      expect(handleExitedSpy.callCount).to.equal(1);
+      expect(onClose.callCount).to.equal(1);
+      expect(onExited.callCount).to.equal(1);
 
       act(() => {
         clock.tick(duration);
       });
 
-      expect(handleCloseSpy.callCount).to.equal(messageCount);
-      expect(handleExitedSpy.callCount).to.equal(1);
+      expect(onClose.callCount).to.equal(messageCount);
+      expect(onExited.callCount).to.equal(1);
 
       act(() => {
         clock.tick(duration / 2);
       });
 
-      expect(handleCloseSpy.callCount).to.equal(messageCount);
-      expect(handleExitedSpy.callCount).to.equal(messageCount);
+      expect(onClose.callCount).to.equal(messageCount);
+      expect(onExited.callCount).to.equal(messageCount);
     });
   });
 
diff --git a/packages/material-ui/src/SpeedDial/SpeedDial.test.js b/packages/material-ui/src/SpeedDial/SpeedDial.test.js
index d3160c493775af..d38936ccd7e828 100644
--- a/packages/material-ui/src/SpeedDial/SpeedDial.test.js
+++ b/packages/material-ui/src/SpeedDial/SpeedDial.test.js
@@ -201,8 +201,11 @@ describe('<SpeedDial />', () => {
       const fab = getByRole('button');
       act(() => {
         fab.focus();
+      });
+      act(() => {
         clock.tick();
       });
+
       expect(handleOpen.callCount).to.equal(1);
       const actions = getAllByRole('menuitem');
       expect(actions.length).to.equal(2);
@@ -224,6 +227,8 @@ describe('<SpeedDial />', () => {
 
       act(() => {
         fab.focus();
+      });
+      act(() => {
         clock.runAll();
       });
 
diff --git a/packages/material-ui/src/Tabs/ScrollbarSize.test.js b/packages/material-ui/src/Tabs/ScrollbarSize.test.js
index 6b7dd3f75b9a79..f3e4faf701b086 100644
--- a/packages/material-ui/src/Tabs/ScrollbarSize.test.js
+++ b/packages/material-ui/src/Tabs/ScrollbarSize.test.js
@@ -22,7 +22,7 @@ describe('<ScrollbarSize />', () => {
       const onChange = spy();
       render(<ScrollbarSize onChange={onChange} />);
 
-      expect(onChange.callCount).to.equal(1);
+      expect(onChange.called).to.equal(true);
     });
   });
 
@@ -33,11 +33,12 @@ describe('<ScrollbarSize />', () => {
       stub(container.firstChild, 'offsetHeight').get(() => 20);
       stub(container.firstChild, 'clientHeight').get(() => 0);
 
-      expect(onChange.callCount).to.equal(1);
+      onChange.resetHistory();
+
       window.dispatchEvent(new window.Event('resize', {}));
       clock.tick(166);
-      expect(onChange.callCount).to.equal(2);
-      expect(onChange.args[1][0]).to.equal(20);
+      expect(onChange.callCount).to.equal(1);
+      expect(onChange.args[0][0]).to.equal(20);
     });
 
     it('should not call if height has not changed from previous resize', () => {
@@ -46,13 +47,14 @@ describe('<ScrollbarSize />', () => {
       stub(container.firstChild, 'offsetHeight').get(() => 20);
       stub(container.firstChild, 'clientHeight').get(() => 0);
 
-      expect(onChange.callCount).to.equal(1);
+      onChange.resetHistory();
+
       window.dispatchEvent(new window.Event('resize', {}));
       clock.tick(166);
       window.dispatchEvent(new window.Event('resize', {}));
       clock.tick(166);
-      expect(onChange.callCount).to.equal(2);
-      expect(onChange.args[1][0]).to.equal(20);
+      expect(onChange.callCount).to.equal(1);
+      expect(onChange.args[0][0]).to.equal(20);
     });
   });
 });
diff --git a/packages/material-ui/src/Tabs/Tabs.test.js b/packages/material-ui/src/Tabs/Tabs.test.js
index 6397fefc6047b5..32d915f1cd8542 100644
--- a/packages/material-ui/src/Tabs/Tabs.test.js
+++ b/packages/material-ui/src/Tabs/Tabs.test.js
@@ -319,8 +319,11 @@ describe('<Tabs />', () => {
           );
         }).toErrorDev([
           'You can provide one of the following values: 1, 3',
-          // StrictMode renders twice
+          // React 18 Strict Effects run mount effects twice
+          React.version.startsWith('18') && 'You can provide one of the following values: 1, 3',
           'You can provide one of the following values: 1, 3',
+          // React 18 Strict Effects run mount effects twice
+          React.version.startsWith('18') && 'You can provide one of the following values: 1, 3',
           'You can provide one of the following values: 1, 3',
           'You can provide one of the following values: 1, 3',
         ]);
@@ -469,12 +472,16 @@ describe('<Tabs />', () => {
         }),
       });
       forceUpdate();
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
       expect(hasLeftScrollButton(container)).to.equal(true);
       expect(hasRightScrollButton(container)).to.equal(true);
       tablistContainer.scrollLeft = 0;
       fireEvent.scroll(container.querySelector(`.${classes.scroller}.${classes.scrollableX}`));
-      clock.tick(166);
+      act(() => {
+        clock.tick(166);
+      });
 
       expect(hasLeftScrollButton(container)).to.equal(false);
       expect(hasRightScrollButton(container)).to.equal(true);
@@ -584,13 +591,17 @@ describe('<Tabs />', () => {
         }),
       });
       forceUpdate();
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
       expect(hasLeftScrollButton(container)).to.equal(true);
       expect(hasRightScrollButton(container)).to.equal(true);
       tablistContainer.scrollLeft = 0;
 
-      window.dispatchEvent(new window.Event('resize', {}));
-      clock.tick(166);
+      act(() => {
+        window.dispatchEvent(new window.Event('resize', {}));
+        clock.tick(166);
+      });
 
       expect(hasLeftScrollButton(container)).to.equal(false);
       expect(hasRightScrollButton(container)).to.equal(true);
@@ -700,17 +711,23 @@ describe('<Tabs />', () => {
       Object.defineProperty(tablistContainer, 'scrollWidth', { value: 100 + 50 + 100 });
       tablistContainer.scrollLeft = 20;
       forceUpdate();
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
       expect(hasLeftScrollButton(container)).to.equal(true);
       expect(hasRightScrollButton(container)).to.equal(true);
 
       fireEvent.click(findScrollButton(container, 'left'));
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
       expect(tablistContainer.scrollLeft).not.to.be.above(0);
 
       tablistContainer.scrollLeft = 0;
       fireEvent.click(findScrollButton(container, 'right'));
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
       expect(tablistContainer.scrollLeft).equal(100);
     });
   });
@@ -755,7 +772,9 @@ describe('<Tabs />', () => {
         right: 30,
       });
       forceUpdate();
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
       expect(tablistContainer.scrollLeft).to.equal(0);
     });
   });
diff --git a/packages/material-ui/src/TextareaAutosize/TextareaAutosize.test.js b/packages/material-ui/src/TextareaAutosize/TextareaAutosize.test.js
index 6fe65d83139925..d070e22655f70c 100644
--- a/packages/material-ui/src/TextareaAutosize/TextareaAutosize.test.js
+++ b/packages/material-ui/src/TextareaAutosize/TextareaAutosize.test.js
@@ -94,7 +94,9 @@ describe('<TextareaAutosize />', () => {
         scrollHeight: 30,
         lineHeight: 15,
       });
-      input.focus();
+      act(() => {
+        input.focus();
+      });
       fireEvent.change(document.activeElement, { target: { value: 'a' } });
       expect(input.style).to.have.property('height', '30px');
       expect(input.style).to.have.property('overflow', 'hidden');
diff --git a/packages/material-ui/src/Tooltip/Tooltip.test.js b/packages/material-ui/src/Tooltip/Tooltip.test.js
index e5ce4ccfe2f237..8bf2760d4444a8 100644
--- a/packages/material-ui/src/Tooltip/Tooltip.test.js
+++ b/packages/material-ui/src/Tooltip/Tooltip.test.js
@@ -468,7 +468,11 @@ describe('<Tooltip />', () => {
         </div>
       );
 
-      const { setProps, getByRole } = render(<AutoFocus />);
+      const { setProps, getByRole } = render(
+        <AutoFocus />,
+        // TODO: https://github.com/reactwg/react-18/discussions/18#discussioncomment-893076
+        { strictEffects: false },
+      );
 
       setProps({ open: true });
       act(() => {
@@ -756,7 +760,9 @@ describe('<Tooltip />', () => {
       expect(getByRole('tooltip')).toBeVisible();
 
       fireEvent.mouseOver(getByRole('tooltip'));
-      clock.tick(111 + 10);
+      act(() => {
+        clock.tick(111 + 10);
+      });
 
       expect(getByRole('tooltip')).not.toBeVisible();
     });
@@ -877,7 +883,9 @@ describe('<Tooltip />', () => {
 
       expect(queryByRole('tooltip')).to.equal(null);
 
-      getByRole('button').focus();
+      act(() => {
+        getByRole('button').focus();
+      });
 
       if (programmaticFocusTriggersFocusVisible()) {
         expect(queryByRole('tooltip')).not.to.equal(null);
@@ -922,7 +930,11 @@ describe('<Tooltip />', () => {
 
       act(() => {
         button.focus();
+      });
+      act(() => {
         button.blur();
+      });
+      act(() => {
         clock.tick(transitionTimeout);
       });
 
diff --git a/packages/material-ui/src/Zoom/Zoom.test.js b/packages/material-ui/src/Zoom/Zoom.test.js
index 17ad8247d3d22c..ebe72d7f12d1f4 100644
--- a/packages/material-ui/src/Zoom/Zoom.test.js
+++ b/packages/material-ui/src/Zoom/Zoom.test.js
@@ -1,7 +1,7 @@
 import * as React from 'react';
 import { expect } from 'chai';
 import { spy, useFakeTimers } from 'sinon';
-import { describeConformance, createClientRender } from 'test/utils';
+import { act, describeConformance, createClientRender } from 'test/utils';
 import { Transition } from 'react-transition-group';
 import Zoom from '@material-ui/core/Zoom';
 
@@ -68,7 +68,9 @@ describe('<Zoom />', () => {
       expect(handleEntering.callCount).to.equal(1);
       expect(handleEntering.args[0][0]).to.equal(child);
 
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
       expect(handleEntered.callCount).to.equal(1);
       expect(handleEntered.args[0][0]).to.equal(child);
 
@@ -84,7 +86,9 @@ describe('<Zoom />', () => {
       expect(handleExiting.callCount).to.equal(1);
       expect(handleExiting.args[0][0]).to.equal(child);
 
-      clock.tick(1000);
+      act(() => {
+        clock.tick(1000);
+      });
       expect(handleExited.callCount).to.equal(1);
       expect(handleExited.args[0][0]).to.equal(child);
     });
diff --git a/packages/material-ui/src/useAutocomplete/useAutocomplete.test.js b/packages/material-ui/src/useAutocomplete/useAutocomplete.test.js
index d2d727998ff5c8..63453cbced05d3 100644
--- a/packages/material-ui/src/useAutocomplete/useAutocomplete.test.js
+++ b/packages/material-ui/src/useAutocomplete/useAutocomplete.test.js
@@ -258,10 +258,16 @@ describe('useAutocomplete', () => {
       "Error: Uncaught [TypeError: Cannot read property 'removeAttribute' of null]",
       'Material-UI: Unable to find the input element.',
       "Error: Uncaught [TypeError: Cannot read property 'removeAttribute' of null]",
+      // strict effects runs effects twice
+      React.version.startsWith('18') && 'Material-UI: Unable to find the input element.',
+      React.version.startsWith('18') &&
+        "Error: Uncaught [TypeError: Cannot read property 'removeAttribute' of null]",
       'The above error occurred in the <ul> component',
       // strict mode renders twice
       React.version.startsWith('16') && 'The above error occurred in the <ul> component',
       'The above error occurred in the <Test> component',
+      // strict effects runs effects twice
+      React.version.startsWith('18') && 'The above error occurred in the <Test> component',
       // strict mode renders twice
       React.version.startsWith('16') && 'The above error occurred in the <Test> component',
     ];
diff --git a/packages/material-ui/src/useMediaQuery/useMediaQuery.test.js b/packages/material-ui/src/useMediaQuery/useMediaQuery.test.js
index 70acd7e9d3e3cd..dd5e239b441857 100644
--- a/packages/material-ui/src/useMediaQuery/useMediaQuery.test.js
+++ b/packages/material-ui/src/useMediaQuery/useMediaQuery.test.js
@@ -33,17 +33,18 @@ function createMatchMedia(width, ref) {
 }
 
 describe('useMediaQuery', () => {
-  before(function beforeHook() {
-    // Only run the test on node.
-    // Waiting for https://github.com/facebook/react/issues/14050
-    if (!/jsdom/.test(window.navigator.userAgent)) {
-      this.skip();
-    }
-  });
-
   const render = createClientRender();
 
-  describe('without feature', () => {
+  describe('without window.matchMedia', () => {
+    let originalMatchmedia;
+    beforeEach(() => {
+      originalMatchmedia = window.matchMedia;
+      delete window.matchMedia;
+    });
+    afterEach(() => {
+      window.matchMedia = originalMatchmedia;
+    });
+
     it('should work without window.matchMedia available', () => {
       expect(typeof window.matchMedia).to.equal('undefined');
       const Test = () => {
@@ -56,7 +57,7 @@ describe('useMediaQuery', () => {
     });
   });
 
-  describe('with feature', () => {
+  describe('with window.matchMedia', () => {
     let matchMediaInstances;
 
     beforeEach(() => {
@@ -244,8 +245,8 @@ describe('useMediaQuery', () => {
       expect(screen.getByTestId('matches').textContent).to.equal('false');
 
       act(() => {
-        matchMediaInstances[0].instance.matches = true;
-        matchMediaInstances[0].listeners[0]();
+        matchMediaInstances[matchMediaInstances.length - 1].instance.matches = true;
+        matchMediaInstances[matchMediaInstances.length - 1].listeners[0]();
       });
       expect(screen.getByTestId('matches').textContent).to.equal('true');
       expect(getRenderCountRef.current()).to.equal(2);
diff --git a/packages/material-ui/src/utils/index.test.js b/packages/material-ui/src/utils/index.test.js
index cee26636609dda..5bb59c8f170893 100644
--- a/packages/material-ui/src/utils/index.test.js
+++ b/packages/material-ui/src/utils/index.test.js
@@ -67,13 +67,11 @@ describe('utils/index.js', () => {
     it('returns a single ref-setter function that forks the ref to its inputs', () => {
       function Component(props) {
         const { innerRef } = props;
-        const ownRef = React.useRef(null);
-        const [, forceUpdate] = React.useState(0);
-        React.useEffect(() => forceUpdate((n) => !n), []);
+        const [ownRefCurrent, ownRef] = React.useState(null);
 
         const handleRef = useForkRef(innerRef, ownRef);
 
-        return <div ref={handleRef}>{ownRef.current ? 'has a ref' : 'has no ref'}</div>;
+        return <div ref={handleRef}>{ownRefCurrent ? 'has a ref' : 'has no ref'}</div>;
       }
 
       const outerRef = React.createRef();
diff --git a/packages/material-ui/test/integration/MenuList.test.js b/packages/material-ui/test/integration/MenuList.test.js
index 83e0df394281eb..3f95648444db6f 100644
--- a/packages/material-ui/test/integration/MenuList.test.js
+++ b/packages/material-ui/test/integration/MenuList.test.js
@@ -146,7 +146,9 @@ describe('<MenuList> integration', () => {
       );
       const menuitems = getAllByRole('menuitem');
 
-      menuitems[0].focus();
+      act(() => {
+        menuitems[0].focus();
+      });
 
       expect(menuitems[0]).toHaveFocus();
       expect(menuitems[0]).to.have.property('tabIndex', 0);
@@ -434,7 +436,9 @@ describe('<MenuList> integration', () => {
         </MenuList>,
       );
       const menu = getByRole('menu');
-      menu.focus();
+      act(() => {
+        menu.focus();
+      });
 
       fireEvent.keyDown(menu, { key: 'a' });
 
@@ -466,8 +470,10 @@ describe('<MenuList> integration', () => {
 
       const menuitem = getByText('Arizona');
       // user click
-      fireEvent.mouseDown(menuitem);
-      menuitem.focus();
+      act(() => {
+        fireEvent.mouseDown(menuitem);
+        menuitem.focus();
+      });
       fireEvent.click(menuitem);
 
       expect(menuitem).toHaveFocus();
diff --git a/packages/material-ui/test/integration/Select.test.js b/packages/material-ui/test/integration/Select.test.js
index 0114d721c8577f..cd2a75999b67a4 100644
--- a/packages/material-ui/test/integration/Select.test.js
+++ b/packages/material-ui/test/integration/Select.test.js
@@ -132,11 +132,11 @@ describe('<Select> integration', () => {
         </FormControl>,
       );
 
+      const trigger = getByRole('button');
       act(() => {
-        const trigger = getByRole('button');
         trigger.focus();
-        fireEvent.keyDown(trigger, { key: 'Enter' });
       });
+      fireEvent.keyDown(trigger, { key: 'Enter' });
 
       expect(getByTestId('label')).to.have.class('focused-label');
     });
diff --git a/scripts/use-react-dist-tag.js b/scripts/use-react-dist-tag.js
index 21d7f06ade6892..1594eb8074244b 100644
--- a/scripts/use-react-dist-tag.js
+++ b/scripts/use-react-dist-tag.js
@@ -50,6 +50,8 @@ async function main(options) {
 
   packageJson.devDependencies['@eps1lon/enzyme-adapter-react-17'] =
     'npm:@eps1lon/enzyme-adapter-react-next';
+  packageJson.devDependencies['@testing-library/react'] =
+    'https://pkg.csb.dev/testing-library/react-testing-library/commit/0e2cf7da/@testing-library/react';
 
   // add newline for clean diff
   fs.writeFileSync(packageJsonPath, `${JSON.stringify(packageJson, null, 2)}${os.EOL}`);
diff --git a/test/utils/createClientRender.tsx b/test/utils/createClientRender.tsx
index 617b26165d8a65..21057cb392e18e 100644
--- a/test/utils/createClientRender.tsx
+++ b/test/utils/createClientRender.tsx
@@ -222,11 +222,19 @@ interface RenderConfiguration {
    * https://testing-library.com/docs/react-testing-library/api#hydrate
    */
   hydrate?: boolean;
+  /**
+   * Set to true if the test fails in React 18.
+   */
+  legacyRoot?: boolean;
   profiler: Profiler;
   /**
    * wrap in React.StrictMode?
    */
   strict?: boolean;
+  /**
+   * Set to `true` if the test fails due to [Strict Effects](https://github.com/reactwg/react-18/discussions/19).
+   */
+  strictEffects?: boolean;
   wrapper?: React.JSXElementConstructor<{}>;
 }
 
@@ -249,12 +257,15 @@ function clientRender(
     container,
     emotionCache,
     hydrate,
+    legacyRoot,
     strict = true,
+    strictEffects = strict,
     profiler,
     wrapper: InnerWrapper = React.Fragment,
   } = configuration;
 
-  const Mode = strict ? React.StrictMode : React.Fragment;
+  const usesLegacyRoot = !React.version.startsWith('18');
+  const Mode = strict && (strictEffects || usesLegacyRoot) ? React.StrictMode : React.Fragment;
   function Wrapper({ children }: { children?: React.ReactNode }) {
     return (
       <Mode>
@@ -273,6 +284,8 @@ function clientRender(
       baseElement,
       container,
       hydrate,
+      // @ts-ignore Available in the `@testing-library/react` fork used when running with React 18
+      legacyRoot,
       queries: { ...queries, ...customQueries },
       wrapper: Wrapper,
     }),
@@ -301,7 +314,11 @@ function clientRender(
 export function createClientRender(
   globalOptions: RenderOptions = {},
 ): (element: React.ReactElement, options?: RenderOptions) => MuiRenderResult {
-  const { strict: globalStrict } = globalOptions;
+  const {
+    legacyRoot: globalLegacyRoot,
+    strict: globalStrict,
+    strictEffects: globalStrictEffects,
+  } = globalOptions;
   // save stack to re-use in test-hooks
   const { stack: createClientRenderStack } = new Error();
 
@@ -392,9 +409,20 @@ export function createClientRender(
       );
     }
 
-    const { strict = globalStrict, ...localOptions } = options;
-
-    return clientRender(element, { ...localOptions, strict, profiler, emotionCache });
+    const {
+      legacyRoot = globalLegacyRoot,
+      strict = globalStrict,
+      strictEffects = globalStrictEffects,
+      ...localOptions
+    } = options;
+    return clientRender(element, {
+      ...localOptions,
+      legacyRoot,
+      strict,
+      strictEffects,
+      profiler,
+      emotionCache,
+    });
   };
 }
 
diff --git a/test/utils/fireDiscreteEvent.js b/test/utils/fireDiscreteEvent.js
index 4bcb6d4fb49046..0b5c32c6bc686a 100644
--- a/test/utils/fireDiscreteEvent.js
+++ b/test/utils/fireDiscreteEvent.js
@@ -1,3 +1,4 @@
+import * as React from 'react';
 import { configure, fireEvent, getConfig } from '@testing-library/react';
 
 const noWrapper = (callback) => callback();
@@ -7,6 +8,11 @@ const noWrapper = (callback) => callback();
  * @returns {void}
  */
 function withMissingActWarningsIgnored(callback) {
+  if (React.version.startsWith('18')) {
+    callback();
+    return;
+  }
+
   const originalConsoleError = console.error;
   console.error = function silenceMissingActWarnings(message, ...args) {
     const isMissingActWarning = /not wrapped in act\(...\)/.test(message);
diff --git a/test/utils/userEvent.ts b/test/utils/userEvent.ts
index d169ea0e836816..c6c4f6dacf6862 100644
--- a/test/utils/userEvent.ts
+++ b/test/utils/userEvent.ts
@@ -8,12 +8,10 @@ export function touch(target: Element): void {
 }
 
 export function mousePress(target: Element): void {
-  if (typeof (React as any).unstable_act === 'function') {
-    (React as any).unstable_act(() => {
-      mouseDown(target);
-      mouseUp(target);
-      click(target);
-    });
+  if (React.version.startsWith('18')) {
+    fireEvent.mouseDown(target);
+    fireEvent.mouseUp(target);
+    fireEvent.click(target);
   } else {
     mouseDown(target);
     mouseUp(target);