diff --git a/flask_oidc/__init__.py b/flask_oidc/__init__.py
index 34d3fd3..22e3053 100644
--- a/flask_oidc/__init__.py
+++ b/flask_oidc/__init__.py
@@ -38,7 +38,8 @@
 from oauth2client.client import flow_from_clientsecrets, OAuth2WebServerFlow,\
     AccessTokenRefreshError, OAuth2Credentials
 import httplib2
-from itsdangerous import JSONWebSignatureSerializer, BadSignature
+from itsdangerous import JSONWebSignatureSerializer, BadSignature, \
+    SignatureExpired
 
 __all__ = ['OpenIDConnect', 'MemoryCredentials']