diff --git a/Doc/library/threading.rst b/Doc/library/threading.rst
index 0489421cdf60e5..cea110e38756a5 100644
--- a/Doc/library/threading.rst
+++ b/Doc/library/threading.rst
@@ -496,6 +496,10 @@ All methods are executed atomically.
 
       There is no return value.
 
+   .. method:: locked()
+      Return true if the lock is acquired.
+
+
 
 .. _rlock-objects: