diff --git a/Lib/weakref.py b/Lib/weakref.py
index 42aba654de5..25b70927e29 100644
--- a/Lib/weakref.py
+++ b/Lib/weakref.py
@@ -33,7 +33,6 @@
            "WeakSet", "WeakMethod", "finalize"]
 
 
-_collections_abc.Set.register(WeakSet)
 _collections_abc.MutableSet.register(WeakSet)
 
 class WeakMethod(ref):