diff --git a/tox.ini b/tox.ini
index c346b5682..cb3846d54 100644
--- a/tox.ini
+++ b/tox.ini
@@ -40,7 +40,7 @@ skipsdist = True
 usedevelop = True
 basepython = python3.6
 deps = pre-commit
-commands = pre-commit run --all-files
+commands = pre-commit run --all-files --show-diff-on-failure
 
 [testenv:py27-xdist]
 deps =