diff --git a/dom/bindings/Bindings.conf b/dom/bindings/Bindings.conf
index b4ce53252baa..08f64d675c34 100644
--- a/dom/bindings/Bindings.conf
+++ b/dom/bindings/Bindings.conf
@@ -707,6 +707,18 @@ DOMInterfaces = {
     'workers': True,
 }],
 
+'InstallPhaseEvent': {
+    'headerFile': 'ServiceWorkerEvents.h',
+    'nativeType': 'mozilla::dom::workers::InstallPhaseEvent',
+    'workers': True
+},
+
+'InstallEvent': {
+    'headerFile': 'ServiceWorkerEvents.h',
+    'nativeType': 'mozilla::dom::workers::InstallEvent',
+    'workers': True
+},
+
 'KeyEvent': {
     'concrete': False
 },
diff --git a/dom/webidl/InstallEvent.webidl b/dom/webidl/InstallEvent.webidl
new file mode 100644
index 000000000000..9c6d40349177
--- /dev/null
+++ b/dom/webidl/InstallEvent.webidl
@@ -0,0 +1,28 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * For more information on this interface, please see
+ * http://slightlyoff.github.io/ServiceWorker/spec/service_worker/index.html
+ */
+
+// While not explicitly restricted to ServiceWorkerGlobalScope, it probably
+// should be. https://github.com/slightlyoff/ServiceWorker/issues/254
+[Constructor(DOMString type, optional InstallEventInit eventInitDict),
+ Func="mozilla::dom::workers::ServiceWorkerEventsVisible"]
+interface InstallEvent : InstallPhaseEvent {
+  // The currently active worker for this scope when this worker is asked to
+  // install itself.
+  // This may be null when a ServiceWorker is being installed for a previously
+  // uncontrolled scope.
+  // https://github.com/slightlyoff/ServiceWorker/issues/260
+  readonly attribute ServiceWorker? activeWorker;
+  void replace();
+};
+
+// Should be in the spec soon to satisfy conventions about events.
+// https://github.com/slightlyoff/ServiceWorker/issues/216.
+dictionary InstallEventInit : EventInit {
+  ServiceWorker? activeWorker = null;
+};
diff --git a/dom/webidl/InstallPhaseEvent.webidl b/dom/webidl/InstallPhaseEvent.webidl
new file mode 100644
index 000000000000..04337749eba3
--- /dev/null
+++ b/dom/webidl/InstallPhaseEvent.webidl
@@ -0,0 +1,17 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * For more information on this interface, please see
+ * http://slightlyoff.github.io/ServiceWorker/spec/service_worker/index.html
+ */
+
+// While not explicitly restricted to ServiceWorkerGlobalScope, it probably
+// should be. https://github.com/slightlyoff/ServiceWorker/issues/254
+[Constructor(DOMString type, optional EventInit eventInitDict),
+ Func="mozilla::dom::workers::ServiceWorkerEventsVisible"]
+interface InstallPhaseEvent : Event {
+  // https://github.com/slightlyoff/ServiceWorker/issues/261
+  void waitUntil(Promise p);
+};
diff --git a/dom/webidl/moz.build b/dom/webidl/moz.build
index 5e7820ebc1f8..5c690310899a 100644
--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -214,6 +214,8 @@ WEBIDL_FILES = [
     'InputEvent.webidl',
     'InputMethod.webidl',
     'InspectorUtils.webidl',
+    'InstallEvent.webidl',
+    'InstallPhaseEvent.webidl',
     'InterAppConnection.webidl',
     'InterAppConnectionRequest.webidl',
     'InterAppMessagePort.webidl',
diff --git a/dom/workers/ServiceWorkerEvents.cpp b/dom/workers/ServiceWorkerEvents.cpp
new file mode 100644
index 000000000000..7b895365afca
--- /dev/null
+++ b/dom/workers/ServiceWorkerEvents.cpp
@@ -0,0 +1,66 @@
+/* -*- Mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 40 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ServiceWorkerEvents.h"
+
+#include "nsContentUtils.h"
+
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/WorkerScope.h"
+#include "mozilla/dom/workers/bindings/ServiceWorker.h"
+#include "mozilla/dom/ServiceWorkerGlobalScopeBinding.h"
+
+using namespace mozilla::dom;
+
+BEGIN_WORKERS_NAMESPACE
+
+bool
+ServiceWorkerEventsVisible(JSContext* aCx, JSObject* aObj)
+{
+  ServiceWorkerGlobalScope* scope = nullptr;
+  nsresult rv = UnwrapObject<prototypes::id::ServiceWorkerGlobalScope_workers,
+                             mozilla::dom::ServiceWorkerGlobalScopeBinding_workers::NativeType>(aObj, scope);
+  return NS_SUCCEEDED(rv) && scope;
+}
+
+InstallPhaseEvent::InstallPhaseEvent(EventTarget* aOwner)
+  : Event(aOwner, nullptr, nullptr)
+{
+}
+
+void
+InstallPhaseEvent::WaitUntil(Promise& aPromise)
+{
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  // Only first caller counts.
+  if (EventPhase() == AT_TARGET && !mPromise) {
+    mPromise = &aPromise;
+  }
+}
+
+NS_IMPL_ADDREF_INHERITED(InstallPhaseEvent, Event)
+NS_IMPL_RELEASE_INHERITED(InstallPhaseEvent, Event)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(InstallPhaseEvent)
+NS_INTERFACE_MAP_END_INHERITING(Event)
+
+NS_IMPL_CYCLE_COLLECTION_INHERITED(InstallPhaseEvent, Event, mPromise)
+
+InstallEvent::InstallEvent(EventTarget* aOwner)
+  : InstallPhaseEvent(aOwner)
+{
+}
+
+NS_IMPL_ADDREF_INHERITED(InstallEvent, InstallPhaseEvent)
+NS_IMPL_RELEASE_INHERITED(InstallEvent, InstallPhaseEvent)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(InstallEvent)
+NS_INTERFACE_MAP_END_INHERITING(InstallPhaseEvent)
+
+NS_IMPL_CYCLE_COLLECTION_INHERITED(InstallEvent, InstallPhaseEvent, mActiveWorker)
+
+END_WORKERS_NAMESPACE
diff --git a/dom/workers/ServiceWorkerEvents.h b/dom/workers/ServiceWorkerEvents.h
new file mode 100644
index 000000000000..73f7f7fd8790
--- /dev/null
+++ b/dom/workers/ServiceWorkerEvents.h
@@ -0,0 +1,133 @@
+/* -*- Mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 40 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_workers_serviceworkerevents_h__
+#define mozilla_dom_workers_serviceworkerevents_h__
+
+#include "mozilla/dom/Event.h"
+#include "mozilla/dom/InstallPhaseEventBinding.h"
+#include "mozilla/dom/InstallEventBinding.h"
+
+namespace mozilla {
+namespace dom {
+  class Promise;
+} // namespace dom
+} // namespace mozilla
+
+BEGIN_WORKERS_NAMESPACE
+
+class ServiceWorker;
+
+bool
+ServiceWorkerEventsVisible(JSContext* aCx, JSObject* aObj);
+
+class InstallPhaseEvent : public Event
+{
+  nsRefPtr<Promise> mPromise;
+
+protected:
+  InstallPhaseEvent(mozilla::dom::EventTarget* aOwner);
+
+public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(InstallPhaseEvent, Event)
+  NS_FORWARD_TO_EVENT
+
+  virtual JSObject* WrapObject(JSContext* aCx) MOZ_OVERRIDE
+  {
+    return mozilla::dom::InstallPhaseEventBinding_workers::Wrap(aCx, this);
+  }
+
+  static already_AddRefed<InstallPhaseEvent>
+  Constructor(mozilla::dom::EventTarget* aOwner,
+              const nsAString& aType,
+              const EventInit& aOptions)
+  {
+    nsRefPtr<InstallPhaseEvent> e = new InstallPhaseEvent(aOwner);
+    bool trusted = e->Init(aOwner);
+    e->InitEvent(aType, aOptions.mBubbles, aOptions.mCancelable);
+    e->SetTrusted(trusted);
+    return e.forget();
+  }
+
+  static already_AddRefed<InstallPhaseEvent>
+  Constructor(const GlobalObject& aGlobal,
+              const nsAString& aType,
+              const EventInit& aOptions,
+              ErrorResult& aRv)
+  {
+    nsCOMPtr<EventTarget> target = do_QueryInterface(aGlobal.GetAsSupports());
+    return Constructor(target, aType, aOptions);
+  }
+
+  void
+  WaitUntil(Promise& aPromise);
+
+  already_AddRefed<Promise>
+  GetPromise() const
+  {
+    nsRefPtr<Promise> p = mPromise;
+    return p.forget();
+  }
+};
+
+class InstallEvent MOZ_FINAL : public InstallPhaseEvent
+{
+  // FIXME(nsm): Bug 982787 will allow actually populating this.
+  nsRefPtr<ServiceWorker> mActiveWorker;
+
+protected:
+  InstallEvent(mozilla::dom::EventTarget* aOwner);
+
+public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(InstallEvent, InstallPhaseEvent)
+  NS_FORWARD_TO_EVENT
+
+  virtual JSObject* WrapObject(JSContext* aCx) MOZ_OVERRIDE
+  {
+    return mozilla::dom::InstallEventBinding_workers::Wrap(aCx, this);
+  }
+
+  static already_AddRefed<InstallEvent>
+  Constructor(mozilla::dom::EventTarget* aOwner,
+              const nsAString& aType,
+              const InstallEventInit& aOptions)
+  {
+    nsRefPtr<InstallEvent> e = new InstallEvent(aOwner);
+    bool trusted = e->Init(aOwner);
+    e->InitEvent(aType, aOptions.mBubbles, aOptions.mCancelable);
+    e->SetTrusted(trusted);
+    e->mActiveWorker = aOptions.mActiveWorker;
+    return e.forget();
+  }
+
+  static already_AddRefed<InstallEvent>
+  Constructor(const GlobalObject& aGlobal,
+              const nsAString& aType,
+              const InstallEventInit& aOptions,
+              ErrorResult& aRv)
+  {
+    nsCOMPtr<EventTarget> owner = do_QueryInterface(aGlobal.GetAsSupports());
+    return Constructor(owner, aType, aOptions);
+  }
+
+  already_AddRefed<ServiceWorker>
+  GetActiveWorker() const
+  {
+    nsRefPtr<ServiceWorker> sw = mActiveWorker;
+    return sw.forget();
+  }
+
+  void
+  Replace()
+  {
+    // FIXME(nsm): Unspecced. Bug 982711
+    NS_WARNING("Not Implemented");
+  };
+};
+
+END_WORKERS_NAMESPACE
+#endif /* mozilla_dom_workers_serviceworkerevents_h__ */
diff --git a/dom/workers/moz.build b/dom/workers/moz.build
index a23fb801c294..69595c784fd0 100644
--- a/dom/workers/moz.build
+++ b/dom/workers/moz.build
@@ -49,6 +49,7 @@ SOURCES += [
     'ScriptLoader.cpp',
     'ServiceWorker.cpp',
     'ServiceWorkerContainer.cpp',
+    'ServiceWorkerEvents.cpp',
     'SharedWorker.cpp',
     'URL.cpp',
     'WorkerPrivate.cpp',