diff --git a/tox.ini b/tox.ini
index 083778e98c50..4174b7659829 100644
--- a/tox.ini
+++ b/tox.ini
@@ -271,7 +271,7 @@ passenv =
 
 [testenv:system-tests3]
 basepython =
-    python3.4
+    python3.5
 commands =
     {[testing]localdeps}
     python {toxinidir}/system_tests/attempt_system_tests.py {posargs}