diff --git a/setup.py b/setup.py
index 41b6f54..405e6f3 100644
--- a/setup.py
+++ b/setup.py
@@ -41,6 +41,7 @@ setup(
         "Issues": "https://github.com/simonw/sqlite-utils/issues",
         "CI": "https://github.com/simonw/sqlite-utils/actions",
     },
+    python_requires=">=3.6",
     classifiers=[
         "Development Status :: 5 - Production/Stable",
         "Intended Audience :: Developers",