diff --git a/vumi/transports/smpp/clientserver/client.py b/vumi/transports/smpp/clientserver/client.py
index da336cd55..1dd44f33e 100644
--- a/vumi/transports/smpp/clientserver/client.py
+++ b/vumi/transports/smpp/clientserver/client.py
@@ -12,13 +12,20 @@
 from smpp.pdu import unpack_pdu
 from smpp.pdu_builder import (
     BindTransceiver, BindTransmitter, BindReceiver, DeliverSMResp, SubmitSM,
-    EnquireLink, EnquireLinkResp, QuerySM)
+    EnquireLink, EnquireLinkResp, QuerySM, PDU)
 from smpp.pdu_inspector import (
     MultipartMessage, detect_multipart, multipart_key)
 
 from vumi import log
 
 
+class UnbindResp(PDU):
+    # pdu_builder doesn't have one of these yet.
+    def __init__(self, sequence_number, **kwargs):
+        super(UnbindResp, self).__init__(
+            'unbind_resp', 'ESME_ROK', sequence_number, **kwargs)
+
+
 def unpacked_pdu_opts(unpacked_pdu):
     pdu_opts = {}
     for opt in unpacked_pdu['body'].get('optional_parameters', []):
@@ -218,6 +225,12 @@ def cancel_drop_connection_call(self):
             self._lose_conn.cancel()
             self._lose_conn = None
 
+    @inlineCallbacks
+    def handle_unbind(self, pdu):
+        yield self.send_pdu(UnbindResp(
+            sequence_number=pdu['header']['sequence_number']))
+        self.transport.loseConnection()
+
     @inlineCallbacks
     def handle_bind_transceiver_resp(self, pdu):
         if pdu['header']['command_status'] == 'ESME_ROK':
diff --git a/vumi/transports/smpp/clientserver/tests/test_client.py b/vumi/transports/smpp/clientserver/tests/test_client.py
index 01c0b4215..f7b5053f2 100644
--- a/vumi/transports/smpp/clientserver/tests/test_client.py
+++ b/vumi/transports/smpp/clientserver/tests/test_client.py
@@ -1,7 +1,7 @@
 from twisted.trial import unittest
 from twisted.internet.task import Clock
 from twisted.internet.defer import inlineCallbacks, returnValue
-from smpp.pdu_builder import DeliverSM, BindTransceiverResp
+from smpp.pdu_builder import DeliverSM, BindTransceiverResp, Unbind
 from smpp.pdu import unpack_pdu
 
 from vumi.tests.utils import LogCatcher, PersistenceMixin
@@ -169,6 +169,14 @@ def test_sequence_rollover(self):
         self.assertEqual(0xFFFF0001, (yield esme.get_next_seq()))
         self.assertEqual(1, (yield esme.get_next_seq()))
 
+    @inlineCallbacks
+    def test_unbind(self):
+        esme = yield self.get_esme()
+
+        yield esme.handle_data(Unbind(1).get_bin())
+
+        self.assertEqual(False, esme.transport.connected)
+
 
 class EsmeTransmitterMixin(EsmeGenericMixin):
     """Transmitter-side tests."""