diff --git a/Lib/ipaddress.py b/Lib/ipaddress.py
index a8edcd1..25bcccd 100644
--- a/Lib/ipaddress.py
+++ b/Lib/ipaddress.py
@@ -1130,7 +1130,7 @@
         """
         unspecified_address = IPv4Address('0.0.0.0')
         if isinstance(self, _BaseAddress):
-            return self in unspecified_address
+            return self == unspecified_address
         return (self.network_address == self.broadcast_address ==
                 unspecified_address)
 
diff --git a/Lib/test/test_ipaddress.py b/Lib/test/test_ipaddress.py
index aff4ff9..5b7d013 100644
--- a/Lib/test/test_ipaddress.py
+++ b/Lib/test/test_ipaddress.py
@@ -837,6 +837,7 @@
         self.assertEqual(False, ipaddress.ip_network('128.0.0.0').is_loopback)
 
         # test addresses
+        self.assertEqual(True, ipaddress.ip_address('0.0.0.0').is_unspecified)
         self.assertEqual(True, ipaddress.ip_address('224.1.1.1').is_multicast)
         self.assertEqual(False, ipaddress.ip_address('240.0.0.0').is_multicast)