diff --git a/docs/requirements.txt b/docs/requirements.txt
index 786cc72bb..bf6571249 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -2,7 +2,7 @@
 python-markdown-math==0.2
 
 alabaster==0.7.8
-Babel==2.3.4
+Babel==2.9.1
 docutils==0.12
 imagesize==0.7.1
 Jinja2==2.8