diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..f25ab60
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,47 @@
+// Type definitions for @node-oauth/express-oauth-server 3.0.0
+// Project: https://github.com/node-oauth/express-oauth-server
+// Definitions by: Arne Schubert <https://github.com/atd-schubert>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 2.3
+
+import * as express from "express";
+import * as OAuth2Server from "@node-oauth/oauth2-server";
+
+declare namespace ExpressOAuthServer {
+  interface Options extends OAuth2Server.ServerOptions {
+    useErrorHandler?: boolean | undefined;
+    continueMiddleware?: boolean | undefined;
+  }
+}
+
+declare class ExpressOAuthServer {
+  server: OAuth2Server;
+
+  constructor(options: ExpressOAuthServer.Options);
+
+  authenticate(
+    options?: OAuth2Server.AuthenticateOptions
+  ): (
+    request: express.Request,
+    response: express.Response,
+    next: express.NextFunction
+  ) => Promise<OAuth2Server.Token>;
+
+  authorize(
+    options?: OAuth2Server.AuthorizeOptions
+  ): (
+    request: express.Request,
+    response: express.Response,
+    next: express.NextFunction
+  ) => Promise<OAuth2Server.AuthorizationCode>;
+
+  token(
+    options?: OAuth2Server.TokenOptions
+  ): (
+    request: express.Request,
+    response: express.Response,
+    next: express.NextFunction
+  ) => Promise<OAuth2Server.Token>;
+}
+
+export = ExpressOAuthServer;
diff --git a/package.json b/package.json
index 6cc9570..3998e76 100644
--- a/package.json
+++ b/package.json
@@ -3,6 +3,7 @@
   "version": "3.0.0",
   "description": "OAuth provider for express",
   "main": "index.js",
+  "typings": "index.d.ts",
   "scripts": {
     "lint": "npx eslint .",
     "lint:fix": "npx eslint . --fix",