diff --git a/setup.py b/setup.py
index 0e2af3f..306039e 100644
--- a/setup.py
+++ b/setup.py
@@ -61,6 +61,7 @@ def get_version():
         'Operating System :: OS Independent',
         'Programming Language :: Python',
         'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3 :: Only',
         'Topic :: Software Development :: Libraries :: Python Modules',
         'Topic :: Software Development :: Quality Assurance',
     ],