diff --git a/tox.ini b/tox.ini
index ff9973f7..c4bf6ad0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -17,7 +17,7 @@ deps =
 setenv =
     LC_CTYPE=en_US.UTF-8
 commands =
-    pre-commit run --all-files
+    pre-commit run --all-files --show-diff-on-failure
 
 [testenv:mypy]
 basepython=python3.8