diff --git a/tox.ini b/tox.ini
index 144dab825..58652da2f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -15,6 +15,8 @@ python =
     3.11: python3.11
 
 [testenv]
+setenv = 
+    MPLBACKEND=agg
 deps =
     -rrequirements/dev.txt
 commands =