diff --git a/types/selenium-webdriver/firefox.d.ts b/types/selenium-webdriver/firefox.d.ts
index 0c2ecdbe92..ce8a14216e 100644
--- a/types/selenium-webdriver/firefox.d.ts
+++ b/types/selenium-webdriver/firefox.d.ts
@@ -149,6 +149,13 @@ export class Profile {
  * Configuration options for the FirefoxDriver.
  */
 export class Options {
+    /**
+     * Sets the browser to be in headless mode.
+     *
+     * @return {!Options} A self reference.
+     */
+    headless(): Options;
+
     /**
      * Sets the profile to use. The profile may be specified as a
      * {@link Profile} object or as the path to an existing Firefox profile to use