diff --git a/keystoneauth1/exceptions/connection.py b/keystoneauth1/exceptions/connection.py
index 19db8bf5..769a875d 100644
--- a/keystoneauth1/exceptions/connection.py
+++ b/keystoneauth1/exceptions/connection.py
@@ -17,7 +17,8 @@ __all__ = ['ConnectionError',
            'ConnectTimeout',
            'ConnectFailure',
            'SSLError',
-           'RetriableConnectionFailure']
+           'RetriableConnectionFailure',
+           'UnknownConnectionError']
 
 
 class RetriableConnectionFailure(Exception):
diff --git a/keystoneauth1/tests/unit/test_session.py b/keystoneauth1/tests/unit/test_session.py
index bbc41bdc..c5a090c3 100644
--- a/keystoneauth1/tests/unit/test_session.py
+++ b/keystoneauth1/tests/unit/test_session.py
@@ -814,3 +814,10 @@ class AdapterTest(utils.TestCase):
 
         self.assertNotIn(self.TEST_URL, self.logger.output)
         self.assertNotIn(response, self.logger.output)
+
+    def test_unknown_connection_error(self):
+        self.stub_url('GET', exc=requests.exceptions.RequestException)
+        self.assertRaises(exceptions.UnknownConnectionError,
+                          client_session.Session().request,
+                          self.TEST_URL,
+                          'GET')