diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6572c16d1d59..94e9f2c1fc60 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 ## master
 
-None
+* `[jest-config]` Add `forceCoverageMatch` to allow collecting coverage from
+  ignored files. ([#5081](https://github.com/facebook/jest/pull/5081))
 
 ## jest 22.0.0
 
diff --git a/docs/Configuration.md b/docs/Configuration.md
index e3e8037681fc..42eb4e0195df 100644
--- a/docs/Configuration.md
+++ b/docs/Configuration.md
@@ -237,6 +237,41 @@ Jest will fail if:
 * The `./src/api/very-important-module.js` file has less than 100% coverage.
 * Every remaining file combined has less than 50% coverage (`global`).
 
+### `forceCoverageMatch` [array<string>]
+
+Default: `['']`
+
+Test files are normally ignored from collecting code coverage. With this option,
+you can overwrite this behavior and include otherwise ignored files in code coverage.
+
+For example, if you have tests in source files named with `.t.js` extension as
+following:
+
+```javascript
+// sum.t.js
+
+export function sum(a,b) {
+  return a + b;
+}
+
+if (process.env.NODE_ENV === 'test') {
+  test('sum', () => {
+    expect(sum(1, 2)).toBe(3);
+  });
+}
+```
+
+You can collect coverage from those files with setting `forceCoverageMatch`.
+```json
+{
+  ...
+  "jest": {
+    "forceCoverageMatch": ["**/*.t.js"]
+  }
+}
+```
+
+
 ### `globals` [object]
 
 Default: `{}`
diff --git a/integration_tests/__tests__/__snapshots__/show_config.test.js.snap b/integration_tests/__tests__/__snapshots__/show_config.test.js.snap
index ad5f154fb672..f1eba0383106 100644
--- a/integration_tests/__tests__/__snapshots__/show_config.test.js.snap
+++ b/integration_tests/__tests__/__snapshots__/show_config.test.js.snap
@@ -13,6 +13,7 @@ exports[`--showConfig outputs config info and exits 1`] = `
         \\"/node_modules/\\"
       ],
       \\"detectLeaks\\": false,
+      \\"forceCoverageMatch\\": [],
       \\"globals\\": {},
       \\"haste\\": {
         \\"providesModuleNodeModules\\": []
diff --git a/packages/jest-config/src/defaults.js b/packages/jest-config/src/defaults.js
index ce68eab6a649..3f35af5fd105 100644
--- a/packages/jest-config/src/defaults.js
+++ b/packages/jest-config/src/defaults.js
@@ -38,6 +38,7 @@ export default ({
   coverageReporters: ['json', 'text', 'lcov', 'clover'],
   detectLeaks: false,
   expand: false,
+  forceCoverageMatch: [],
   globalSetup: null,
   globalTeardown: null,
   globals: {},
diff --git a/packages/jest-config/src/index.js b/packages/jest-config/src/index.js
index 9f50d4a068e0..7cd8eccbfce5 100644
--- a/packages/jest-config/src/index.js
+++ b/packages/jest-config/src/index.js
@@ -130,6 +130,7 @@ const getConfigs = (
       cwd: options.cwd,
       detectLeaks: options.detectLeaks,
       displayName: options.displayName,
+      forceCoverageMatch: options.forceCoverageMatch,
       globals: options.globals,
       haste: options.haste,
       moduleDirectories: options.moduleDirectories,
diff --git a/packages/jest-config/src/normalize.js b/packages/jest-config/src/normalize.js
index 749fb078bf02..e7fba4434f83 100644
--- a/packages/jest-config/src/normalize.js
+++ b/packages/jest-config/src/normalize.js
@@ -459,6 +459,7 @@ export default function normalize(options: InitialOptions, argv: Argv) {
       case 'expand':
       case 'globals':
       case 'findRelatedTests':
+      case 'forceCoverageMatch':
       case 'forceExit':
       case 'listTests':
       case 'logHeapUsage':
diff --git a/packages/jest-config/src/valid_config.js b/packages/jest-config/src/valid_config.js
index b2ae2930104d..c1559a7b5419 100644
--- a/packages/jest-config/src/valid_config.js
+++ b/packages/jest-config/src/valid_config.js
@@ -37,6 +37,7 @@ export default ({
   },
   displayName: 'project-name',
   expand: false,
+  forceCoverageMatch: ['**/*.t.js'],
   forceExit: false,
   globalSetup: 'setup.js',
   globalTeardown: 'teardown.js',
diff --git a/packages/jest-runtime/src/__tests__/should_instrument.test.js b/packages/jest-runtime/src/__tests__/should_instrument.test.js
new file mode 100644
index 000000000000..48e79734227c
--- /dev/null
+++ b/packages/jest-runtime/src/__tests__/should_instrument.test.js
@@ -0,0 +1,151 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+
+import shouldInstrument from '../should_instrument';
+
+describe('should_instrument', () => {
+  const defaultFilename = 'source_file.test.js';
+  const defaultOptions = {
+    collectCoverage: true,
+  };
+  const defaultConfig = {
+    rootDir: '/',
+  };
+
+  describe('should return true', () => {
+    const testShouldInstrument = (
+      filename = defaultFilename,
+      options = defaultOptions,
+      config = defaultConfig,
+    ) => {
+      const result = shouldInstrument(filename, options, config);
+      expect(result).toBe(true);
+    };
+
+    it('when testRegex provided and file is not a test file', () => {
+      testShouldInstrument('source_file.js', defaultOptions, {
+        testRegex: '.*\\.(test)\\.(js)$',
+      });
+    });
+
+    it('when testMatch is provided and file is not a test file', () => {
+      testShouldInstrument('source_file.js', defaultOptions, {
+        testMatch: ['**/?(*.)(test).js'],
+      });
+    });
+
+    it('should return true when file is in collectCoverageOnlyFrom when provided', () => {
+      testShouldInstrument(
+        'collect/only/from/here.js',
+
+        {
+          collectCoverage: true,
+          collectCoverageOnlyFrom: {'collect/only/from/here.js': true},
+        },
+        defaultConfig,
+      );
+    });
+
+    it('should return true when filename matches collectCoverageFrom', () => {
+      testShouldInstrument(
+        'do/collect/coverage.js',
+        {
+          collectCoverage: true,
+          collectCoverageFrom: ['!**/dont/**/*.js', '**/do/**/*.js'],
+        },
+        defaultConfig,
+      );
+    });
+
+    it('should return true if the file is not in coveragePathIgnorePatterns', () => {
+      testShouldInstrument('do/collect/coverage.js', defaultOptions, {
+        coveragePathIgnorePatterns: ['dont'],
+        rootDir: '/',
+      });
+    });
+
+    it('should return true if file is a testfile but forceCoverageMatch is set', () => {
+      testShouldInstrument('do/collect/sum.coverage.test.js', defaultOptions, {
+        forceCoverageMatch: ['**/*.(coverage).(test).js'],
+        rootDir: '/',
+        testRegex: '.*\\.(test)\\.(js)$',
+      });
+    });
+  });
+
+  describe('should return false', () => {
+    const testShouldInstrument = (
+      filename = defaultFilename,
+      options = defaultOptions,
+      config = defaultConfig,
+    ) => {
+      const result = shouldInstrument(filename, options, config);
+      expect(result).toBe(false);
+    };
+
+    it('if collectCoverage is falsy', () => {
+      testShouldInstrument(
+        'source_file.js',
+        {
+          collectCoverage: false,
+        },
+        defaultConfig,
+      );
+    });
+
+    it('when testRegex provided and filename is a test file', () => {
+      testShouldInstrument(defaultFilename, defaultOptions, {
+        testRegex: '.*\\.(test)\\.(js)$',
+      });
+    });
+
+    it('when testMatch is provided and file is a test file', () => {
+      testShouldInstrument(defaultFilename, defaultOptions, {
+        testMatch: ['**/?(*.)(test).js'],
+      });
+    });
+
+    it('when file is not in collectCoverageOnlyFrom when provided', () => {
+      testShouldInstrument(
+        'source_file.js',
+        {
+          collectCoverage: true,
+          collectCoverageOnlyFrom: {'collect/only/from/here.js': true},
+        },
+        defaultConfig,
+      );
+    });
+
+    it('when filename does not match collectCoverageFrom', () => {
+      testShouldInstrument(
+        'dont/collect/coverage.js',
+        {
+          collectCoverage: true,
+          collectCoverageFrom: ['!**/dont/**/*.js', '**/do/**/*.js'],
+        },
+        defaultConfig,
+      );
+    });
+
+    it('if the file is in coveragePathIgnorePatterns', () => {
+      testShouldInstrument('dont/collect/coverage.js', defaultOptions, {
+        coveragePathIgnorePatterns: ['dont'],
+        rootDir: '/',
+      });
+    });
+
+    it('if file is in mock patterns', () => {
+      const filename =
+        process.platform === 'win32'
+          ? 'dont\\__mocks__\\collect\\coverage.js'
+          : 'dont/__mocks__/collect/coverage.js';
+
+      testShouldInstrument(filename, defaultOptions, defaultConfig);
+    });
+  });
+});
diff --git a/packages/jest-runtime/src/should_instrument.js b/packages/jest-runtime/src/should_instrument.js
index 48745ddbbea0..0a663ee56378 100644
--- a/packages/jest-runtime/src/should_instrument.js
+++ b/packages/jest-runtime/src/should_instrument.js
@@ -27,6 +27,14 @@ export default function shouldInstrument(
     return false;
   }
 
+  if (
+    config.forceCoverageMatch &&
+    config.forceCoverageMatch.length &&
+    micromatch.any(filename, config.forceCoverageMatch)
+  ) {
+    return true;
+  }
+
   if (config.testRegex && filename.match(config.testRegex)) {
     return false;
   }
diff --git a/test_utils.js b/test_utils.js
index dbed2652d5b4..9ae8c272dd59 100644
--- a/test_utils.js
+++ b/test_utils.js
@@ -70,6 +70,7 @@ const DEFAULT_PROJECT_CONFIG: ProjectConfig = {
   cwd: '/test_root_dir/',
   detectLeaks: false,
   displayName: undefined,
+  forceCoverageMatch: [],
   globals: {},
   haste: {
     providesModuleNodeModules: [],
diff --git a/types/Config.js b/types/Config.js
index e02b2f5fdc80..b9ee6cd422fa 100644
--- a/types/Config.js
+++ b/types/Config.js
@@ -31,6 +31,7 @@ export type DefaultOptions = {|
   coveragePathIgnorePatterns: Array<string>,
   coverageReporters: Array<string>,
   expand: boolean,
+  forceCoverageMatch: Array<Glob>,
   globals: ConfigGlobals,
   globalSetup: ?string,
   globalTeardown: ?string,
@@ -86,6 +87,7 @@ export type InitialOptions = {
   displayName?: string,
   expand?: boolean,
   findRelatedTests?: boolean,
+  forceCoverageMatch?: Array<Glob>,
   forceExit?: boolean,
   json?: boolean,
   globals?: ConfigGlobals,
@@ -212,6 +214,7 @@ export type ProjectConfig = {|
   cwd: Path,
   detectLeaks: boolean,
   displayName: ?string,
+  forceCoverageMatch: Array<Glob>,
   globals: ConfigGlobals,
   haste: HasteConfig,
   moduleDirectories: Array<string>,