diff --git a/doc/utils/requirements.txt b/doc/utils/requirements.txt
index df5d939365..ac4e010147 100644
--- a/doc/utils/requirements.txt
+++ b/doc/utils/requirements.txt
@@ -1,4 +1,4 @@
-Sphinx
+Sphinx >= 5.0.0, <7.0.0
 sphinxcontrib-spelling
 sphinxcontrib-jquery
 git+https://github.com/akohlmey/sphinx-fortran@parallel-read