diff --git a/lib/spack/docs/requirements.txt b/lib/spack/docs/requirements.txt
index 879fe33874579b..fc22924f8b3f56 100644
--- a/lib/spack/docs/requirements.txt
+++ b/lib/spack/docs/requirements.txt
@@ -8,6 +8,6 @@ pygments==2.18.0
 urllib3==2.2.3
 pytest==8.3.3
 isort==5.13.2
-black==24.10.0
+black==25.9.0
 flake8==7.1.1
 mypy==1.11.1