diff --git a/Lib/unittest/mock.py b/Lib/unittest/mock.py
index 7ef7e7180b31c2..3ed54b3ba230ed 100644
--- a/Lib/unittest/mock.py
+++ b/Lib/unittest/mock.py
@@ -3012,9 +3012,7 @@ class ThreadingMixin(Base):
     DEFAULT_TIMEOUT = None
 
     def _get_child_mock(self, /, **kw):
-        if "timeout" in kw:
-            kw["timeout"] = kw.pop("timeout")
-        elif isinstance(kw.get("parent"), ThreadingMixin):
+        if isinstance(kw.get("parent"), ThreadingMixin):
             kw["timeout"] = kw["parent"]._mock_wait_timeout
         elif isinstance(kw.get("_new_parent"), ThreadingMixin):
             kw["timeout"] = kw["_new_parent"]._mock_wait_timeout