diff --git a/setup.py b/setup.py
index a8677b14..71eb0f54 100755
--- a/setup.py
+++ b/setup.py
@@ -5,7 +5,7 @@
 from setuptools import find_packages, setup
 
 # When creating the sdist, make sure the django.mo file also exists:
-if "sdist" in sys.argv or "develop" in sys.argv:
+if ("sdist" in sys.argv or "develop" in sys.argv) and not os.environ.get("TOX_WORK_DIR", ""):
     os.chdir("polymorphic")
     try:
         from django.core import management