diff --git a/socketio/packet.py b/socketio/packet.py
index dd9f859..570708b 100644
--- a/socketio/packet.py
+++ b/socketio/packet.py
@@ -101,6 +101,9 @@ class Packet(object):
             else:
                 self.namespace = ep[0:sep]
                 ep = ep[sep + 1:]
+            q = self.namespace.find('?')
+            if q != -1:
+                self.namespace = self.namespace[0:q]
         if ep and ep[0].isdigit():
             self.id = 0
             while ep[0].isdigit():
diff --git a/tests/test_packet.py b/tests/test_packet.py
index f4d2207..9602789 100644
--- a/tests/test_packet.py
+++ b/tests/test_packet.py
@@ -97,6 +97,13 @@ class TestPacket(unittest.TestCase):
         self.assertEqual(pkt.namespace, '/bar')
         self.assertEqual(pkt.encode(), '2/bar,["foo"]')
 
+    def test_decode_namespace_with_query_string(self):
+        # some Socket.IO clients mistakenly attach the query string to the
+        # namespace
+        pkt = packet.Packet(encoded_packet='2/bar?a=b,["foo"]')
+        self.assertEqual(pkt.namespace, '/bar')
+        self.assertEqual(pkt.encode(), '2/bar,["foo"]')
+
     def test_encode_namespace_no_data(self):
         pkt = packet.Packet(packet_type=packet.EVENT, namespace='/bar')
         self.assertEqual(pkt.encode(), '2/bar')