diff --git a/src/core/oauth2-authorize.js b/src/core/oauth2-authorize.js
index 2e36010e..fd3a4afc 100644
--- a/src/core/oauth2-authorize.js
+++ b/src/core/oauth2-authorize.js
@@ -64,7 +64,8 @@ export default function authorize ( { auth, authActions, errActions, configs, au
     }
   }
 
-  let url = [schema.get("authorizationUrl"), query.join("&")].join("?")
+  let authorizationUrl = schema.get("authorizationUrl")
+  let url = [authorizationUrl, query.join("&")].join(authorizationUrl.indexOf("?") === -1 ? "?" : "&")
 
   // pass action authorizeOauth2 and authentication data through window
   // to authorize with oauth2
diff --git a/test/core/oauth2-authorize.js b/test/core/oauth2-authorize.js
new file mode 100644
index 00000000..c4fed4ba
--- /dev/null
+++ b/test/core/oauth2-authorize.js
@@ -0,0 +1,39 @@
+/* eslint-env mocha */
+import expect, { createSpy } from "expect"
+import { fromJS } from "immutable"
+import win from "core/window"
+import oauth2Authorize from "core/oauth2-authorize"
+
+describe("oauth2", function () {
+
+  let mockSchema = {
+    flow: "accessCode",
+    authorizationUrl: "https://testAuthorizationUrl"
+  }
+
+  let authConfig = {
+    auth: { schema: { get: (key)=> mockSchema[key] } }, 
+    authActions: {}, 
+    errActions: {}, 
+    configs: { oauth2RedirectUrl: "" }, 
+    authConfigs: {}
+  }
+
+  describe("authorize redirect", function () {
+
+    it("should build authorize url", function() {
+      win.open = createSpy()
+      oauth2Authorize(authConfig)
+      expect(win.open.calls.length).toEqual(1)
+      expect(win.open.calls[0].arguments[0]).toMatch("https://testAuthorizationUrl?response_type=code&redirect_uri=&state=")
+    })
+
+    it("should append query paramters to authorizeUrl with query parameters", function() {
+      win.open = createSpy()
+      mockSchema.authorizationUrl = "https://testAuthorizationUrl?param=1"
+      oauth2Authorize(authConfig)
+      expect(win.open.calls.length).toEqual(1)
+      expect(win.open.calls[0].arguments[0]).toMatch("https://testAuthorizationUrl?param=1&response_type=code&redirect_uri=&state=")
+    })
+  })
+})