diff --git a/setup.py b/setup.py
index f160489d9e55b8ebdbe1b450899b9d38ab0c99ec..74b31b574df63c80c900b24c6a41debcb3e63385 100644
--- a/setup.py
+++ b/setup.py
@@ -36,6 +36,7 @@ setup(name="pymbolic",
       url="http://mathema.tician.de/software/pymbolic",
 
       packages=find_packages(),
+      python_requires="~=3.6",
       install_requires=[
           "pytools>=2",
           "pytest>=2.3",