diff --git a/flask_oauthlib/client.py b/flask_oauthlib/client.py
index 6dc7bd35..7f10b12a 100644
--- a/flask_oauthlib/client.py
+++ b/flask_oauthlib/client.py
@@ -440,7 +440,7 @@ def request(self, url, data=None, headers=None, format='urlencoded',
         )
         return OAuthResponse(resp, content, self.content_type)
 
-    def authorize(self, callback=None, state=None):
+    def authorize(self, callback=None, state=None, **kwargs):
         """
         Returns a redirect response to the remote authorization URL with
         the signed callback given.
@@ -449,6 +449,7 @@ def authorize(self, callback=None, state=None):
         :param state: an optional value to embed in the OAuth request.
                       Use this if you want to pass around application
                       state (e.g. CSRF tokens).
+        :param kwargs: add optional key/value pairs to the query string
         """
         if self.request_token_url:
             token = self.generate_request_token(callback)[0]
@@ -459,6 +460,8 @@ def authorize(self, callback=None, state=None):
             assert callback is not None, 'Callback is required OAuth2'
 
             params = dict(self.request_token_params) or {}
+            params.update(**kwargs)
+
             client = self.make_client()
 
             if 'scope' in params: