diff --git a/toolkit/components/filepicker/nsFileView.cpp b/toolkit/components/filepicker/nsFileView.cpp
index d833120d91e9..b296237c7beb 100644
--- a/toolkit/components/filepicker/nsFileView.cpp
+++ b/toolkit/components/filepicker/nsFileView.cpp
@@ -25,6 +25,7 @@
 #include "nsAutoPtr.h"
 #include "nsIMutableArray.h"
 #include "nsTArray.h"
+#include "mozilla/Attributes.h"
 
 #include "nsWildCard.h"
 
@@ -34,7 +35,7 @@ class nsIDOMDataTransfer;
                             { 0x91, 0x10, 0x81, 0x46, 0x61, 0x4c, 0xa7, 0xf0 } }
 #define NS_FILECOMPLETE_CONTRACTID "@mozilla.org/autocomplete/search;1?name=file"
 
-class nsFileResult : public nsIAutoCompleteResult
+class nsFileResult MOZ_FINAL : public nsIAutoCompleteResult
 {
 public:
   // aSearchString is the text typed into the autocomplete widget
@@ -169,7 +170,7 @@ NS_IMETHODIMP nsFileResult::RemoveValueAt(PRInt32 rowIndex, bool removeFromDb)
   return NS_OK;
 }
 
-class nsFileComplete : public nsIAutoCompleteSearch
+class nsFileComplete MOZ_FINAL : public nsIAutoCompleteSearch
 {
 public:
   NS_DECL_ISUPPORTS
diff --git a/toolkit/components/remote/nsGTKRemoteService.h b/toolkit/components/remote/nsGTKRemoteService.h
index 4dd0edb6ff52..ee067f42066f 100644
--- a/toolkit/components/remote/nsGTKRemoteService.h
+++ b/toolkit/components/remote/nsGTKRemoteService.h
@@ -14,8 +14,9 @@
 
 #include "nsInterfaceHashtable.h"
 #include "nsXRemoteService.h"
+#include "mozilla/Attributes.h"
 
-class nsGTKRemoteService : public nsXRemoteService
+class nsGTKRemoteService MOZ_FINAL : public nsXRemoteService
 {
 public:
   // We will be a static singleton, so don't use the ordinary methods.
diff --git a/toolkit/system/unixproxy/nsUnixSystemProxySettings.cpp b/toolkit/system/unixproxy/nsUnixSystemProxySettings.cpp
index 70364478221c..7d612c196c7f 100644
--- a/toolkit/system/unixproxy/nsUnixSystemProxySettings.cpp
+++ b/toolkit/system/unixproxy/nsUnixSystemProxySettings.cpp
@@ -17,8 +17,9 @@
 #include "nsISupportsPrimitives.h"
 #include "nsIGSettingsService.h"
 #include "nsInterfaceHashtable.h"
+#include "mozilla/Attributes.h"
 
-class nsUnixSystemProxySettings : public nsISystemProxySettings {
+class nsUnixSystemProxySettings MOZ_FINAL : public nsISystemProxySettings {
 public:
   NS_DECL_ISUPPORTS
   NS_DECL_NSISYSTEMPROXYSETTINGS