diff --git a/requirements.in b/requirements.in
index 754d4bbc..994bec4f 100644
--- a/requirements.in
+++ b/requirements.in
@@ -12,4 +12,4 @@ cmake
 
 jupyter-book
 flake8
-sphinx<7.3
+sphinx<7.3  # https://github.com/sphinx-doc/sphinx/issues/12290