diff --git a/pip/req/req_install.py b/pip/req/req_install.py
index 305eefe188e..2dbb8e9d4ba 100644
--- a/pip/req/req_install.py
+++ b/pip/req/req_install.py
@@ -633,6 +633,7 @@ def uninstall(self, auto_confirm=False):
                     paths_to_remove.add(path)
                     paths_to_remove.add(path + '.py')
                     paths_to_remove.add(path + '.pyc')
+                    paths_to_remove.add(path + '.pyo')
 
         elif distutils_egg_info:
             raise UninstallationError(