diff --git a/setup.py b/setup.py
index 45fcba8..2048c3c 100644
--- a/setup.py
+++ b/setup.py
@@ -63,6 +63,7 @@ def finalize_options(self):
     license="LICENSE.txt",
     long_description=open("README.rst").read(),
     long_description_content_type="text/x-rst",
+    python_requires=">=3.4",
     packages=["clade"],
     package_data={
         "clade": [