diff --git a/tox.ini b/tox.ini
index 205fe1531..9a11df98c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -50,7 +50,9 @@ commands =
 
 [testenv:py36]
 # git inside of ratchet.sh needs $HOME.
-passenv = HOME LC_ALL
+passenv = HOME
+setenv =
+       LANG=en_US.UTF-8
 commands = {toxinidir}/misc/python3/ratchet.sh
 
 [testenv:integration]