diff --git a/lib/stripe/errors.rb b/lib/stripe/errors.rb
index c5a5e756..f689ac32 100644
--- a/lib/stripe/errors.rb
+++ b/lib/stripe/errors.rb
@@ -114,6 +114,12 @@ module Stripe
       end
     end
 
+    # InvalidClientError is raised when the client doesn't belong to you, or
+    # the API key mode (live or test) doesn't match the client mode. Or the
+    # stripe_user_id doesn't exist or isn't connected to your application.
+    class InvalidClientError < OAuthError
+    end
+
     # InvalidGrantError is raised when a specified code doesn't exist, is
     # expired, has been used, or doesn't belong to you; a refresh token doesn't
     # exist, or doesn't belong to you; or if an API key's mode (live or test)
diff --git a/lib/stripe/stripe_client.rb b/lib/stripe/stripe_client.rb
index 6df836f3..b8949bf0 100644
--- a/lib/stripe/stripe_client.rb
+++ b/lib/stripe/stripe_client.rb
@@ -312,6 +312,7 @@ module Stripe
       }]
 
       case error_code
+      when 'invalid_client'            then OAuth::InvalidClientError.new(*args)
       when 'invalid_grant'             then OAuth::InvalidGrantError.new(*args)
       when 'invalid_request'           then OAuth::InvalidRequestError.new(*args)
       when 'invalid_scope'             then OAuth::InvalidScopeError.new(*args)
diff --git a/test/stripe/stripe_client_test.rb b/test/stripe/stripe_client_test.rb
index 4d9da93b..1caea2d4 100644
--- a/test/stripe/stripe_client_test.rb
+++ b/test/stripe/stripe_client_test.rb
@@ -368,6 +368,24 @@ module Stripe
           assert_equal('invalid_grant', e.code)
           assert_equal('This authorization code has already been used. All tokens issued with this code have been revoked.', e.message)
         end
+
+        should "raise OAuth::InvalidClientError when error is a string with value 'invalid_client'" do
+          stub_request(:post, "#{Stripe.connect_base}/oauth/deauthorize").
+            to_return(body: JSON.generate({
+              error: "invalid_client",
+              error_description: "This application is not connected to stripe account acct_19tLK7DSlTMT26Mk, or that account does not exist.",
+            }), status: 401)
+
+          client = StripeClient.new
+          opts = {api_base: Stripe.connect_base}
+          e = assert_raises Stripe::OAuth::InvalidClientError do
+            client.execute_request(:post, '/oauth/deauthorize', opts)
+          end
+
+          assert_equal(401, e.http_status)
+          assert_equal('invalid_client', e.code)
+          assert_equal('This application is not connected to stripe account acct_19tLK7DSlTMT26Mk, or that account does not exist.', e.message)
+        end
       end
 
       context "idempotency keys" do