diff --git a/messenger/messenger.d.ts b/messenger/messenger.d.ts
new file mode 100644
index 000000000..b874eb356
--- /dev/null
+++ b/messenger/messenger.d.ts
@@ -0,0 +1,27 @@
+// Type definitions for Messenger.js 1.2.1
+// Project: https://github.com/HubSpot/messenger
+// Definitions by: Derek Cicerone <https://github.com/derekcicerone>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+interface IMessenger {
+    (): Messenger;
+    options: MessengerOptions;
+}
+
+interface Messenger {
+    post(message: Message): void;
+    hideAll(): void;
+}
+
+interface Message {
+    message: string;
+    hideAfter?: number;
+    showCloseButton?: boolean;
+    type?: string;
+}
+
+interface MessengerOptions {
+    theme?: string;
+}
+
+declare var Messenger: IMessenger;