diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..7faabeb
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,33 @@
+declare module "whois" {
+  interface WhoisOptions {
+    server?: string | { host: string; port: number };
+    follow?: number;
+    timeout?: number;
+    verbose?: boolean;
+    bind?: string;
+    proxy?: {
+      ipaddress: string;
+      port: number;
+      type?: number;
+    };
+    punycode?: boolean;
+    encoding?: string;
+  }
+
+  interface WhoisResult {
+    server: string;
+    data: string;
+  }
+
+  type WhoisCallback = (
+    err: Error | null,
+    data: string | WhoisResult[]
+  ) => void;
+
+  function lookup(addr: string, callback: WhoisCallback): void;
+  function lookup(
+    addr: string,
+    options: WhoisOptions,
+    callback: WhoisCallback
+  ): void;
+}