diff --git a/layout/base/nsCSSFrameConstructor.cpp b/layout/base/nsCSSFrameConstructor.cpp
index eff9a4408d74..a89828ee2442 100644
--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -47,7 +47,6 @@
 #include "nsCRT.h"
 #include "nsIAtom.h"
 #include "nsIURL.h"
-#include "nsISupportsArray.h"
 #include "nsHashtable.h"
 #include "nsIHTMLDocument.h"
 #include "nsIStyleRule.h"
@@ -90,7 +89,6 @@
 #include "nsCSSPseudoElements.h"
 #include "nsIDeviceContext.h"
 #include "nsTextFragment.h"
-#include "nsISupportsArray.h"
 #include "nsIAnonymousContentCreator.h"
 #include "nsFrameManager.h"
 #include "nsLegendFrame.h"
diff --git a/layout/base/nsIPresShell.h b/layout/base/nsIPresShell.h
index 72011ea894de..e1272f205e40 100644
--- a/layout/base/nsIPresShell.h
+++ b/layout/base/nsIPresShell.h
@@ -86,7 +86,6 @@ class nsFrameSelection;
 class nsFrameManager;
 class nsILayoutHistoryState;
 class nsIReflowCallback;
-class nsISupportsArray;
 class nsIDOMNode;
 class nsIRegion;
 class nsIStyleFrameConstruction;
diff --git a/layout/inspector/src/inDOMUtils.h b/layout/inspector/src/inDOMUtils.h
index fd73e3347c5b..1bff266338d4 100644
--- a/layout/inspector/src/inDOMUtils.h
+++ b/layout/inspector/src/inDOMUtils.h
@@ -41,7 +41,6 @@
 #include "inIDOMUtils.h"
 
 #include "nsIEventStateManager.h"
-#include "nsISupportsArray.h"
 #include "nsIInspectorCSSUtils.h"
 
 class inDOMUtils : public inIDOMUtils
diff --git a/layout/xul/base/src/nsListBoxBodyFrame.cpp b/layout/xul/base/src/nsListBoxBodyFrame.cpp
index a185aa05472a..2f1fe43cdec1 100644
--- a/layout/xul/base/src/nsListBoxBodyFrame.cpp
+++ b/layout/xul/base/src/nsListBoxBodyFrame.cpp
@@ -43,7 +43,6 @@
 
 #include "nsCOMPtr.h"
 #include "nsGridRowGroupLayout.h"
-#include "nsISupportsArray.h"
 #include "nsIServiceManager.h"
 #include "nsGkAtoms.h"
 #include "nsIContent.h"
diff --git a/layout/xul/base/src/nsMenuBarListener.cpp b/layout/xul/base/src/nsMenuBarListener.cpp
index 21b1f7716b57..6b2529d7c435 100644
--- a/layout/xul/base/src/nsMenuBarListener.cpp
+++ b/layout/xul/base/src/nsMenuBarListener.cpp
@@ -59,7 +59,6 @@
 
 #include "nsIEventStateManager.h"
 
-#include "nsISupportsArray.h"
 #include "nsContentUtils.h"
 
 /*
diff --git a/layout/xul/base/src/nsMenuFrame.h b/layout/xul/base/src/nsMenuFrame.h
index e5cd6c58466f..dffecc5a05fd 100644
--- a/layout/xul/base/src/nsMenuFrame.h
+++ b/layout/xul/base/src/nsMenuFrame.h
@@ -54,7 +54,6 @@
 #include "nsIMenuFrame.h"
 #include "nsXULPopupManager.h"
 #include "nsITimer.h"
-#include "nsISupportsArray.h"
 #include "nsIDOMText.h"
 #include "nsIContent.h"
 #include "nsIScrollableViewProvider.h"
diff --git a/layout/xul/base/src/nsScrollbarFrame.h b/layout/xul/base/src/nsScrollbarFrame.h
index b7c9f84b3fb7..317b5075de50 100644
--- a/layout/xul/base/src/nsScrollbarFrame.h
+++ b/layout/xul/base/src/nsScrollbarFrame.h
@@ -46,7 +46,6 @@
 #include "nsBoxFrame.h"
 #include "nsIScrollbarFrame.h"
 
-class nsISupportsArray;
 class nsIScrollbarMediator;
 
 nsIFrame* NS_NewScrollbarFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
diff --git a/layout/xul/base/src/nsSliderFrame.h b/layout/xul/base/src/nsSliderFrame.h
index e09f07f0ac51..3fcce2952a18 100644
--- a/layout/xul/base/src/nsSliderFrame.h
+++ b/layout/xul/base/src/nsSliderFrame.h
@@ -48,7 +48,6 @@
 
 class nsString;
 class nsIScrollbarListener;
-class nsISupportsArray;
 class nsITimer;
 class nsSliderFrame;
 
diff --git a/layout/xul/base/src/nsSplitterFrame.cpp b/layout/xul/base/src/nsSplitterFrame.cpp
index ba5984422d0a..bc61afc6c6c9 100644
--- a/layout/xul/base/src/nsSplitterFrame.cpp
+++ b/layout/xul/base/src/nsSplitterFrame.cpp
@@ -45,7 +45,6 @@
 
 #include "nsSplitterFrame.h"
 #include "nsGkAtoms.h"
-#include "nsISupportsArray.h"
 #include "nsIDOMElement.h"
 #include "nsIDOMXULElement.h"
 #include "nsIDOMDocument.h"
diff --git a/layout/xul/base/src/nsSplitterFrame.h b/layout/xul/base/src/nsSplitterFrame.h
index 58cbe36f185d..ed7925ac566f 100644
--- a/layout/xul/base/src/nsSplitterFrame.h
+++ b/layout/xul/base/src/nsSplitterFrame.h
@@ -45,7 +45,6 @@
 
 #include "nsBoxFrame.h"
 
-class nsISupportsArray;
 class nsSplitterFrameInner;
 
 nsIFrame* NS_NewSplitterFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
diff --git a/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp b/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp
index 9cd2cc2e2475..9c2488d8c360 100644
--- a/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp
+++ b/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp
@@ -47,7 +47,6 @@
  * ***** END LICENSE BLOCK ***** */
 
 #include "nsCOMPtr.h"
-#include "nsISupportsArray.h"
 #include "nsPresContext.h"
 #include "nsINameSpaceManager.h"