diff --git a/setup.py b/setup.py
index 2f8dafd21..cf7c6b333 100755
--- a/setup.py
+++ b/setup.py
@@ -102,6 +102,8 @@ setup(
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3 :: Only',
+        'Programming Language :: Python :: Implementation :: CPython',
+        'Programming Language :: Python :: Implementation :: PyPy',
         'Topic :: Internet :: WWW/HTTP',
     ],
     project_urls={