diff --git a/dom/xbl/nsXBLBinding.h b/dom/xbl/nsXBLBinding.h
index c2af9a993db8ec..2fbe31e232e8d8 100644
--- a/dom/xbl/nsXBLBinding.h
+++ b/dom/xbl/nsXBLBinding.h
@@ -37,7 +37,7 @@ class nsAnonymousContentList;
 // *********************************************************************/
 // The XBLBinding class
 
-class nsXBLBinding
+class nsXBLBinding MOZ_FINAL
 {
 public:
   nsXBLBinding(nsXBLPrototypeBinding* aProtoBinding);
diff --git a/dom/xbl/nsXBLDocumentInfo.h b/dom/xbl/nsXBLDocumentInfo.h
index adbb00035c2c27..aade93513315be 100644
--- a/dom/xbl/nsXBLDocumentInfo.h
+++ b/dom/xbl/nsXBLDocumentInfo.h
@@ -15,7 +15,7 @@
 class nsXBLPrototypeBinding;
 class nsXBLDocGlobalObject;
 
-class nsXBLDocumentInfo : public nsSupportsWeakReference
+class nsXBLDocumentInfo MOZ_FINAL : public nsSupportsWeakReference
 {
 public:
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
diff --git a/dom/xbl/nsXBLProtoImpl.h b/dom/xbl/nsXBLProtoImpl.h
index ab421e2730264b..a32b4e839e04e8 100644
--- a/dom/xbl/nsXBLProtoImpl.h
+++ b/dom/xbl/nsXBLProtoImpl.h
@@ -15,7 +15,7 @@
 class nsXBLPrototypeBinding;
 class nsXBLProtoImplAnonymousMethod;
 
-class nsXBLProtoImpl
+class nsXBLProtoImpl MOZ_FINAL
 {
 public:
   nsXBLProtoImpl()
diff --git a/dom/xbl/nsXBLPrototypeBinding.h b/dom/xbl/nsXBLPrototypeBinding.h
index ca6b6d23e3ceaf..27b4d8f355f926 100644
--- a/dom/xbl/nsXBLPrototypeBinding.h
+++ b/dom/xbl/nsXBLPrototypeBinding.h
@@ -31,7 +31,7 @@ class nsXBLProtoImplField;
 // Instances of this class are owned by the nsXBLDocumentInfo object returned
 // by XBLDocumentInfo().  Consumers who want to refcount things should refcount
 // that.
-class nsXBLPrototypeBinding
+class nsXBLPrototypeBinding MOZ_FINAL
 {
 public:
   nsIContent* GetBindingElement() const { return mBinding; }
diff --git a/dom/xbl/nsXBLService.h b/dom/xbl/nsXBLService.h
index d23a03f12f4b2a..208bc751383d6f 100644
--- a/dom/xbl/nsXBLService.h
+++ b/dom/xbl/nsXBLService.h
@@ -32,8 +32,8 @@ class EventTarget;
 }
 }
 
-class nsXBLService : public nsIObserver,
-                     public nsSupportsWeakReference
+class nsXBLService MOZ_FINAL : public nsIObserver,
+                               public nsSupportsWeakReference
 {
   NS_DECL_ISUPPORTS