diff --git a/tox.ini b/tox.ini
index da9eb0e0..6a32366a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,3 +13,5 @@ extras =
     dev
 commands =
     pytest -v --color=yes --cov=brainrender --cov-report=xml
+passenv =
+    DISPLAY