diff --git a/dom/base/Navigator.cpp b/dom/base/Navigator.cpp
index 0f7f2b756e..026ae15836 100644
--- a/dom/base/Navigator.cpp
+++ b/dom/base/Navigator.cpp
@@ -1532,6 +1532,14 @@ Navigator::Clipboard()
   return mClipboard;
 }
 
+/* static */
+bool
+Navigator::Webdriver()
+{
+  // We don't support Selenium or marionette, so this is always false.
+  return false;
+}
+
 #ifdef MOZ_EME
 static nsCString
 ToCString(const nsString& aString)
diff --git a/dom/base/Navigator.h b/dom/base/Navigator.h
index 10f9573ee9..d674f5cedc 100644
--- a/dom/base/Navigator.h
+++ b/dom/base/Navigator.h
@@ -219,6 +219,8 @@ public:
   
   dom::Clipboard* Clipboard();
 
+  static bool Webdriver();
+
   void GetLanguages(nsTArray<nsString>& aLanguages);
 
   bool MozE10sEnabled();
diff --git a/dom/webidl/Navigator.webidl b/dom/webidl/Navigator.webidl
index f2212de392..4541210a08 100644
--- a/dom/webidl/Navigator.webidl
+++ b/dom/webidl/Navigator.webidl
@@ -12,6 +12,7 @@
  * https://dvcs.w3.org/hg/gamepad/raw-file/default/gamepad.html#navigator-interface-extension
  * http://www.w3.org/TR/beacon/#sec-beacon-method
  * https://html.spec.whatwg.org/#navigatorconcurrenthardware
+ * https://w3c.github.io/webdriver/webdriver-spec.html#interface
  *
  * © Copyright 2004-2020 Apple Computer, Inc., Mozilla Foundation,
  * Opera Software ASA and Moonchild Productions. You are granted a license to use,
@@ -31,6 +32,7 @@ Navigator implements NavigatorStorageUtils;
 Navigator implements NavigatorConcurrentHardware;
 Navigator implements NavigatorStorage;
 Navigator implements NavigatorGlobalPrivacyControl;
+Navigator implements NavigatorAutomationInformation;
 
 [NoInterfaceObject, Exposed=(Window,Worker)]
 interface NavigatorID {
@@ -334,3 +336,10 @@ partial interface Navigator {
   [Pref="dom.events.asyncClipboard", SecureContext, SameObject]
   readonly attribute Clipboard clipboard;
 };
+
+// https://w3c.github.io/webdriver/webdriver-spec.html#interface
+[NoInterfaceObject, Exposed=Window]
+interface NavigatorAutomationInformation {
+  [Pref="dom.webdriver.enabled"]
+  readonly attribute boolean webdriver;
+};
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 56c82aa1d9..9d11726d47 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -5259,6 +5259,9 @@ pref("media.seekToNextFrame.enabled", true);
 // return the maximum number of cores that navigator.hardwareConcurrency returns
 pref("dom.maxHardwareConcurrency", 16);
 
+// Exposes the navigator.webdriver attribute.
+pref("dom.webdriver.enabled", true);
+
 // Shutdown the async osfile worker if it's no longer needed.
 pref("osfile.reset_worker_delay", 30000);