diff --git a/pyproject.toml b/pyproject.toml
index ebdd954..39a8b00 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -49,7 +49,7 @@ dev = [
     "black",
 ]
 docs = [
-    "sphinx~=3.3.1",
+    "sphinx>=3.3.1,<7.3.0",
     "sphinx-book-theme~=0.0.39",
     "sphinx-autodoc-typehints~=1.11.1",
     "sphinx-copybutton~=0.3.1",