diff --git a/setup.py b/setup.py
index a9515ac9..c84a3935 100644
--- a/setup.py
+++ b/setup.py
@@ -73,6 +73,8 @@
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: Implementation :: CPython",
+        "Programming Language :: Python :: Implementation :: PyPy",
     ],
     test_suite="tests",
     tests_require=test_requirements,