diff --git a/setup.py b/setup.py
index 398709f1..325f6a2e 100644
--- a/setup.py
+++ b/setup.py
@@ -93,6 +93,7 @@ setup(
     license='MIT',
     url='http://gunicorn.org',
 
+    python_requires='>=2.6, !=3.0.*, !=3.1.*',
     classifiers=CLASSIFIERS,
     zip_safe=False,
     packages=find_packages(exclude=['examples', 'tests']),