diff --git a/packages/authentication-oauth/src/strategy.ts b/packages/authentication-oauth/src/strategy.ts
index 9d7e00508a..1a2358872f 100644
--- a/packages/authentication-oauth/src/strategy.ts
+++ b/packages/authentication-oauth/src/strategy.ts
@@ -73,7 +73,7 @@ export class OAuthStrategy extends AuthenticationBaseStrategy {
     return null;
   }
 
-  async getRedirect (data: AuthenticationResult|Error, params?: Params) {
+  async getRedirect (data: AuthenticationResult|Error, params?: Params): Promise<string | null> {
     const queryRedirect = (params && params.redirect) || '';
     const { redirect } = this.authentication.configuration.oauth;