diff --git a/requirements-doc.txt b/requirements-doc.txt
index 84e67ef..9a5cdc5 100644
--- a/requirements-doc.txt
+++ b/requirements-doc.txt
@@ -1,3 +1,3 @@
 # List required packages in this file, one per line.
-mpl-sphinx-theme~=3.8.0
+mpl-sphinx-theme~=3.9.0
 myst-parser