diff --git a/lib/spack/docs/requirements.txt b/lib/spack/docs/requirements.txt
index 18e2a26f13ffc6..aae69a4291a8eb 100644
--- a/lib/spack/docs/requirements.txt
+++ b/lib/spack/docs/requirements.txt
@@ -10,4 +10,4 @@ pytest==7.4.4
 isort==5.13.2
 black==23.12.1
 flake8==7.0.0
-mypy==1.8.0
+mypy==1.9.0