diff --git a/accessible/html/HTMLImageMapAccessible.cpp b/accessible/html/HTMLImageMapAccessible.cpp
index 23fd5bae7036..6715d5485959 100644
--- a/accessible/html/HTMLImageMapAccessible.cpp
+++ b/accessible/html/HTMLImageMapAccessible.cpp
@@ -10,7 +10,6 @@
 #include "DocAccessible-inl.h"
 #include "Role.h"
 
-#include "nsIDOMHTMLCollection.h"
 #include "nsIServiceManager.h"
 #include "nsIDOMElement.h"
 #include "nsIFrame.h"
diff --git a/accessible/html/HTMLTableAccessible.cpp b/accessible/html/HTMLTableAccessible.cpp
index 8280882ce66c..65a2bb1b6791 100644
--- a/accessible/html/HTMLTableAccessible.cpp
+++ b/accessible/html/HTMLTableAccessible.cpp
@@ -22,7 +22,7 @@
 #include "nsIDOMRange.h"
 #include "nsISelectionPrivate.h"
 #include "nsIDOMNodeList.h"
-#include "nsIDOMHTMLCollection.h"
+#include "nsIHTMLCollection.h"
 #include "nsIDocument.h"
 #include "nsIMutableArray.h"
 #include "nsIPersistentProperties2.h"
diff --git a/dom/base/AnonymousContent.cpp b/dom/base/AnonymousContent.cpp
index fc4fa4128213..a3383bb86575 100644
--- a/dom/base/AnonymousContent.cpp
+++ b/dom/base/AnonymousContent.cpp
@@ -10,7 +10,6 @@
 #include "nsComputedDOMStyle.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsIDocument.h"
-#include "nsIDOMHTMLCollection.h"
 #include "nsIFrame.h"
 #include "nsStyledElement.h"
 #include "HTMLCanvasElement.h"
diff --git a/dom/base/nsContentList.cpp b/dom/base/nsContentList.cpp
index a0744fa3af5d..6a0f0d9203a3 100644
--- a/dom/base/nsContentList.cpp
+++ b/dom/base/nsContentList.cpp
@@ -506,8 +506,7 @@ nsContentList::WrapObject(JSContext *cx, JS::Handle<JSObject*> aGivenProto)
 }
 
 NS_IMPL_ISUPPORTS_INHERITED(nsContentList, nsBaseContentList,
-                            nsIHTMLCollection, nsIDOMHTMLCollection,
-                            nsIMutationObserver)
+                            nsIHTMLCollection, nsIMutationObserver)
 
 uint32_t
 nsContentList::Length(bool aDoFlush)
diff --git a/dom/base/nsContentList.h b/dom/base/nsContentList.h
index b4c707279f8a..28700bca5a10 100644
--- a/dom/base/nsContentList.h
+++ b/dom/base/nsContentList.h
@@ -150,11 +150,9 @@ public:
   {
   }
 
-  // nsIDOMHTMLCollection
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(nsEmptyContentList,
                                            nsBaseContentList)
-  NS_DECL_NSIDOMHTMLCOLLECTION
   // nsIDOMNodeList, which we also implement.
   NS_DECL_NSIDOMNODELIST
 
@@ -337,8 +335,6 @@ protected:
   }
 public:
 
-  // nsIDOMHTMLCollection
-  NS_DECL_NSIDOMHTMLCOLLECTION
   // nsIDOMNodeList, which we also implement.
   NS_DECL_NSIDOMNODELIST
 
diff --git a/dom/base/nsDocument.cpp b/dom/base/nsDocument.cpp
index 7ce560ee880f..ead087972386 100644
--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -585,9 +585,6 @@ public:
 
   NS_DECL_ISUPPORTS_INHERITED
 
-  // nsIDOMHTMLCollection
-  NS_DECL_NSIDOMHTMLCOLLECTION
-
   virtual nsINode* GetParentObject() override
   {
     return nsSimpleContentList::GetParentObject();
@@ -668,7 +665,7 @@ private:
 };
 
 NS_IMPL_ISUPPORTS_INHERITED(SimpleHTMLCollection, nsSimpleContentList,
-                            nsIHTMLCollection, nsIDOMHTMLCollection)
+                            nsIHTMLCollection)
 
 } // namespace dom
 } // namespace mozilla
diff --git a/dom/html/HTMLFormControlsCollection.cpp b/dom/html/HTMLFormControlsCollection.cpp
index f282e712b3b8..8094db43e992 100644
--- a/dom/html/HTMLFormControlsCollection.cpp
+++ b/dom/html/HTMLFormControlsCollection.cpp
@@ -143,8 +143,7 @@ NS_IMPL_CYCLE_COLLECTION_TRACE_END
 NS_INTERFACE_TABLE_HEAD(HTMLFormControlsCollection)
   NS_WRAPPERCACHE_INTERFACE_TABLE_ENTRY
   NS_INTERFACE_TABLE(HTMLFormControlsCollection,
-                     nsIHTMLCollection,
-                     nsIDOMHTMLCollection)
+                     nsIHTMLCollection)
   NS_INTERFACE_TABLE_TO_MAP_SEGUE_CYCLE_COLLECTION(HTMLFormControlsCollection)
 NS_INTERFACE_MAP_END
 
@@ -153,7 +152,7 @@ NS_IMPL_CYCLE_COLLECTING_ADDREF(HTMLFormControlsCollection)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(HTMLFormControlsCollection)
 
 
-// nsIDOMHTMLCollection interface
+// nsIHTMLCollection interface
 
 uint32_t
 HTMLFormControlsCollection::Length()
diff --git a/dom/html/HTMLFormControlsCollection.h b/dom/html/HTMLFormControlsCollection.h
index 6cccf8998650..71802743d61a 100644
--- a/dom/html/HTMLFormControlsCollection.h
+++ b/dom/html/HTMLFormControlsCollection.h
@@ -35,9 +35,6 @@ public:
 
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
 
-  // nsIDOMHTMLCollection interface
-  NS_DECL_NSIDOMHTMLCOLLECTION
-
   virtual uint32_t Length() override;
   virtual Element* GetElementAt(uint32_t index) override;
   virtual nsINode* GetParentObject() override;
diff --git a/dom/html/HTMLInputElement.cpp b/dom/html/HTMLInputElement.cpp
index 8179d1538cc8..ddba97709a0f 100644
--- a/dom/html/HTMLInputElement.cpp
+++ b/dom/html/HTMLInputElement.cpp
@@ -57,7 +57,6 @@
 #include "nsPresState.h"
 #include "nsIDOMEvent.h"
 #include "nsIDOMNodeList.h"
-#include "nsIDOMHTMLCollection.h"
 #include "nsLinebreakConverter.h" //to strip out carriage returns
 #include "nsReadableUtils.h"
 #include "nsUnicharUtils.h"
diff --git a/dom/html/HTMLOptionElement.cpp b/dom/html/HTMLOptionElement.cpp
index b1b2ed0b7d6a..4984644b3fe5 100644
--- a/dom/html/HTMLOptionElement.cpp
+++ b/dom/html/HTMLOptionElement.cpp
@@ -13,7 +13,6 @@
 #include "nsIFormControl.h"
 #include "nsIForm.h"
 #include "nsIDOMNode.h"
-#include "nsIDOMHTMLCollection.h"
 #include "nsISelectControlFrame.h"
 
 // Notify/query select frame for selected state
diff --git a/dom/html/HTMLOptionsCollection.cpp b/dom/html/HTMLOptionsCollection.cpp
index e51e506cdd14..48eb3ce7cf3a 100644
--- a/dom/html/HTMLOptionsCollection.cpp
+++ b/dom/html/HTMLOptionsCollection.cpp
@@ -96,8 +96,7 @@ NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(HTMLOptionsCollection, mElements)
 NS_INTERFACE_TABLE_HEAD(HTMLOptionsCollection)
   NS_WRAPPERCACHE_INTERFACE_TABLE_ENTRY
   NS_INTERFACE_TABLE(HTMLOptionsCollection,
-                     nsIHTMLCollection,
-                     nsIDOMHTMLCollection)
+                     nsIHTMLCollection)
   NS_INTERFACE_TABLE_TO_MAP_SEGUE_CYCLE_COLLECTION(HTMLOptionsCollection)
 NS_INTERFACE_MAP_END
 
diff --git a/dom/html/HTMLOptionsCollection.h b/dom/html/HTMLOptionsCollection.h
index 11f2bb609a02..5c80ccab0343 100644
--- a/dom/html/HTMLOptionsCollection.h
+++ b/dom/html/HTMLOptionsCollection.h
@@ -36,7 +36,6 @@ public:
   explicit HTMLOptionsCollection(HTMLSelectElement* aSelect);
 
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
-  NS_DECL_NSIDOMHTMLCOLLECTION
 
   // nsWrapperCache
   using nsWrapperCache::GetWrapperPreserveColor;
diff --git a/dom/html/HTMLTableElement.cpp b/dom/html/HTMLTableElement.cpp
index 25d0932eea1d..621687ab61bd 100644
--- a/dom/html/HTMLTableElement.cpp
+++ b/dom/html/HTMLTableElement.cpp
@@ -32,7 +32,6 @@ public:
   explicit TableRowsCollection(HTMLTableElement* aParent);
 
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
-  NS_DECL_NSIDOMHTMLCOLLECTION
 
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
@@ -218,8 +217,7 @@ NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_LAST_RELEASE(TableRowsCollection,
 
 NS_INTERFACE_TABLE_HEAD(TableRowsCollection)
   NS_WRAPPERCACHE_INTERFACE_TABLE_ENTRY
-  NS_INTERFACE_TABLE(TableRowsCollection, nsIHTMLCollection,
-                     nsIDOMHTMLCollection, nsIMutationObserver)
+  NS_INTERFACE_TABLE(TableRowsCollection, nsIHTMLCollection, nsIMutationObserver)
   NS_INTERFACE_TABLE_TO_MAP_SEGUE_CYCLE_COLLECTION(TableRowsCollection)
 NS_INTERFACE_MAP_END
 
diff --git a/dom/html/nsHTMLDocument.h b/dom/html/nsHTMLDocument.h
index 9d456ae67a76..6b58e57d68d8 100644
--- a/dom/html/nsHTMLDocument.h
+++ b/dom/html/nsHTMLDocument.h
@@ -10,7 +10,7 @@
 #include "nsDocument.h"
 #include "nsIHTMLDocument.h"
 #include "nsIDOMHTMLDocument.h"
-#include "nsIDOMHTMLCollection.h"
+#include "nsIHTMLCollection.h"
 #include "nsIScriptElement.h"
 #include "nsTArray.h"
 
diff --git a/dom/html/nsIHTMLCollection.h b/dom/html/nsIHTMLCollection.h
index bd6bdc9561cc..a4d3f50f77b5 100644
--- a/dom/html/nsIHTMLCollection.h
+++ b/dom/html/nsIHTMLCollection.h
@@ -7,7 +7,7 @@
 #ifndef nsIHTMLCollection_h___
 #define nsIHTMLCollection_h___
 
-#include "nsIDOMHTMLCollection.h"
+#include "nsISupports.h"
 #include "nsStringFwd.h"
 #include "nsTArrayForwardDeclare.h"
 #include "nsWrapperCache.h"
@@ -30,7 +30,7 @@ class Element;
 /**
  * An internal interface
  */
-class nsIHTMLCollection : public nsIDOMHTMLCollection
+class nsIHTMLCollection : public nsISupports
 {
 public:
   NS_DECLARE_STATIC_IID_ACCESSOR(NS_IHTMLCOLLECTION_IID)
diff --git a/dom/interfaces/base/domstubs.idl b/dom/interfaces/base/domstubs.idl
index 2c0ab43b262b..cf25d68d8783 100644
--- a/dom/interfaces/base/domstubs.idl
+++ b/dom/interfaces/base/domstubs.idl
@@ -59,7 +59,6 @@ interface nsIDOMEventListener;
 // HTML
 interface nsIDOMHTMLElement;
 interface nsIDOMHTMLFormElement;
-interface nsIDOMHTMLCollection;
 interface nsIDOMHTMLHeadElement;
 
 // CSS
diff --git a/dom/interfaces/html/moz.build b/dom/interfaces/html/moz.build
index 4eccd0119db9..a4bd15fd5ad3 100644
--- a/dom/interfaces/html/moz.build
+++ b/dom/interfaces/html/moz.build
@@ -8,7 +8,6 @@ with Files("**"):
     BUG_COMPONENT = ("Core", "DOM")
 
 XPIDL_SOURCES += [
-    'nsIDOMHTMLCollection.idl',
     'nsIDOMHTMLDocument.idl',
     'nsIDOMHTMLElement.idl',
     'nsIDOMHTMLFormElement.idl',
diff --git a/dom/interfaces/html/nsIDOMHTMLCollection.idl b/dom/interfaces/html/nsIDOMHTMLCollection.idl
deleted file mode 100644
index 57dc16d0c718..000000000000
--- a/dom/interfaces/html/nsIDOMHTMLCollection.idl
+++ /dev/null
@@ -1,22 +0,0 @@
-/* -*- 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/. */
-
-#include "domstubs.idl"
-
-/**
- * The nsIDOMHTMLCollection interface is an interface to a collection
- * of [X]HTML elements.
- *
- * This interface is trying to follow the DOM Level 2 HTML specification:
- * http://www.w3.org/TR/DOM-Level-2-HTML/
- *
- * with changes from the work-in-progress WHATWG HTML specification:
- * http://www.whatwg.org/specs/web-apps/current-work/
- */
-
-[uuid(bb07f567-5b37-4172-92aa-7d00ceed4809)]
-interface nsIDOMHTMLCollection : nsISupports
-{
-};
diff --git a/dom/plugins/base/nsPluginInstanceOwner.cpp b/dom/plugins/base/nsPluginInstanceOwner.cpp
index b34c466472d3..6ba30af11d6d 100644
--- a/dom/plugins/base/nsPluginInstanceOwner.cpp
+++ b/dom/plugins/base/nsPluginInstanceOwner.cpp
@@ -46,7 +46,6 @@ using mozilla::DefaultXDisplay;
 #include "nsIScrollableFrame.h"
 #include "nsIDocShell.h"
 #include "ImageContainer.h"
-#include "nsIDOMHTMLCollection.h"
 #include "GLContext.h"
 #include "EGLUtils.h"
 #include "nsIContentInlines.h"
diff --git a/dom/webbrowserpersist/WebBrowserPersistLocalDocument.cpp b/dom/webbrowserpersist/WebBrowserPersistLocalDocument.cpp
index 3c4576f8346c..83c17b72d0c1 100644
--- a/dom/webbrowserpersist/WebBrowserPersistLocalDocument.cpp
+++ b/dom/webbrowserpersist/WebBrowserPersistLocalDocument.cpp
@@ -25,7 +25,6 @@
 #include "nsIDOMAttr.h"
 #include "nsIDOMComment.h"
 #include "nsIDOMDocument.h"
-#include "nsIDOMHTMLCollection.h"
 #include "nsIDOMHTMLDocument.h"
 #include "nsIDOMHTMLInputElement.h"
 #include "nsIDOMHTMLMediaElement.h"
diff --git a/widget/GfxInfoBase.cpp b/widget/GfxInfoBase.cpp
index b5e8560b6f47..4808045b5f83 100644
--- a/widget/GfxInfoBase.cpp
+++ b/widget/GfxInfoBase.cpp
@@ -21,7 +21,6 @@
 #include "nsIObserver.h"
 #include "nsIObserverService.h"
 #include "nsIDOMElement.h"
-#include "nsIDOMHTMLCollection.h"
 #include "nsIDOMNode.h"
 #include "nsIDOMNodeList.h"
 #include "nsTArray.h"
diff --git a/xpcom/reflect/xptinfo/ShimInterfaceInfo.cpp b/xpcom/reflect/xptinfo/ShimInterfaceInfo.cpp
index bd950c414950..a2c3f3dc763e 100644
--- a/xpcom/reflect/xptinfo/ShimInterfaceInfo.cpp
+++ b/xpcom/reflect/xptinfo/ShimInterfaceInfo.cpp
@@ -45,7 +45,6 @@
 #include "nsIDOMFormData.h"
 #include "nsIDOMGeoPositionError.h"
 #include "nsIDOMHistory.h"
-#include "nsIDOMHTMLCollection.h"
 #include "nsIDOMHTMLDocument.h"
 #include "nsIDOMHTMLElement.h"
 #include "nsIDOMHTMLFormElement.h"
@@ -140,7 +139,6 @@
 #include "mozilla/dom/HTMLAnchorElementBinding.h"
 #include "mozilla/dom/HTMLAreaElementBinding.h"
 #include "mozilla/dom/HTMLButtonElementBinding.h"
-#include "mozilla/dom/HTMLCollectionBinding.h"
 #include "mozilla/dom/HTMLDocumentBinding.h"
 #include "mozilla/dom/HTMLElementBinding.h"
 #include "mozilla/dom/HTMLFormElementBinding.h"
@@ -290,7 +288,6 @@ const ComponentsInterfaceShimEntry kComponentsInterfaceShimMap[] =
   DEFINE_SHIM_WITH_CUSTOM_INTERFACE(nsIFrameLoader, FrameLoader),
   DEFINE_SHIM_WITH_CUSTOM_INTERFACE(nsIDOMGeoPositionError, PositionError),
   DEFINE_SHIM(History),
-  DEFINE_SHIM(HTMLCollection),
   DEFINE_SHIM(HTMLDocument),
   DEFINE_SHIM(HTMLElement),
   DEFINE_SHIM(HTMLFormElement),