diff --git a/constraints/ci.txt b/constraints/ci.txt
index b9a01c8..43ef801 100644
--- a/constraints/ci.txt
+++ b/constraints/ci.txt
@@ -2,5 +2,5 @@
 # Pinned to the versions the tree is actually clean under (house rule shared with the
 # sibling tools).
 pytest==9.1.1
-ruff==0.16.1
+ruff==0.16.5
 mypy==2.3.0