diff --git a/tox.ini b/tox.ini
index 9f0e77753..9ee3923f2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -25,3 +25,4 @@ deps =
 [testenv:windows]
 commands =
     {toxinidir}/bin/runtests.bat []
+sitepackages = False