diff --git a/Lib/pathlib.py b/Lib/pathlib.py
index 531a699a40..9abe2aec95 100644
--- a/Lib/pathlib.py
+++ b/Lib/pathlib.py
@@ -808,6 +808,9 @@ def __ge__(self, other):
     def __class_getitem__(cls, type):
         return cls
 
+    def __contains__(self, key):
+        return key in self.__str__()
+
     drive = property(attrgetter('_drv'),
                      doc="""The drive prefix (letter or UNC path), if any.""")