diff --git a/setup.py b/setup.py
index 0c80a568..8327e508 100644
--- a/setup.py
+++ b/setup.py
@@ -31,6 +31,7 @@
         'twisted': ['twisted'],
     },
     test_suite="tests",
+    python_requires=">=2.6, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*",
     classifiers=[
         "Development Status :: 4 - Beta",
         "Intended Audience :: Developers",