diff --git a/setup.py b/setup.py
index acf77a708936..71ce34d36be5 100644
--- a/setup.py
+++ b/setup.py
@@ -184,5 +184,6 @@ def run(self):
                         ],
       # Same here.
       extras_require={'dmypy': 'psutil >= 4.0'},
+      python_requires=">=3.5",
       include_package_data=True,
       )