diff --git a/setup.py b/setup.py
index 495ebd20f52f2ed007ac4c61b109291522b58028..aa8d70e16363b6a3fb969a235b3e18ede31645b4 100644
--- a/setup.py
+++ b/setup.py
@@ -248,6 +248,7 @@ def main():
                 "numpy",
                 ],
 
+            python_requires="~=3.6",
             install_requires=[
                 "numpy",
                 "pytools>=2017.6",