diff --git a/toolkit/components/filepicker/nsFilePicker.manifest b/toolkit/components/filepicker/nsFilePicker.manifest
index 203c87fc347..06c2e8956f3 100644
--- a/toolkit/components/filepicker/nsFilePicker.manifest
+++ b/toolkit/components/filepicker/nsFilePicker.manifest
@@ -1,4 +1,4 @@
 component {54ae32f8-1dd2-11b2-a209-df7c505370f8} nsFilePicker.js
-#ifndef MOZ_WIDGET_GTK2
+#ifndef MOZ_WIDGET_GTK
 contract @mozilla.org/filepicker;1 {54ae32f8-1dd2-11b2-a209-df7c505370f8}
 #endif
diff --git a/toolkit/components/remote/nsGTKRemoteService.cpp b/toolkit/components/remote/nsGTKRemoteService.cpp
index 3bbb8bcdbcd..5782dd1f4a3 100644
--- a/toolkit/components/remote/nsGTKRemoteService.cpp
+++ b/toolkit/components/remote/nsGTKRemoteService.cpp
@@ -155,7 +155,11 @@ nsGTKRemoteService::HandleCommandsFor(GtkWidget* widget,
 
   gtk_widget_add_events(widget, GDK_PROPERTY_CHANGE_MASK);
 
+#if (MOZ_WIDGET_GTK == 2)
   Window window = GDK_WINDOW_XWINDOW(widget->window);
+#else
+  Window window = gdk_x11_window_get_xid(gtk_widget_get_window(widget));
+#endif
   nsXRemoteService::HandleCommandsFor(window);
 
 }
@@ -168,8 +172,13 @@ nsGTKRemoteService::HandlePropertyChange(GtkWidget *aWidget,
   if (pevent->state == GDK_PROPERTY_NEW_VALUE) {
     Atom changedAtom = gdk_x11_atom_to_xatom(pevent->atom);
 
-    return HandleNewProperty(GDK_WINDOW_XWINDOW(pevent->window),
-                             GDK_DISPLAY(),
+#if (MOZ_WIDGET_GTK == 2)
+    XID window = GDK_WINDOW_XWINDOW(pevent->window);
+#else
+    XID window = gdk_x11_window_get_xid(gtk_widget_get_window(aWidget));
+#endif
+    return HandleNewProperty(window,
+                             GDK_DISPLAY_XDISPLAY(gdk_display_get_default()),
                              pevent->time, changedAtom, aThis);
   }
   return FALSE;
diff --git a/toolkit/content/widgets/findbar.xml b/toolkit/content/widgets/findbar.xml
index 2b1457c5fdb..aca73388d3a 100644
--- a/toolkit/content/widgets/findbar.xml
+++ b/toolkit/content/widgets/findbar.xml
@@ -185,7 +185,7 @@
       <xul:label anonid="find-label" class="findbar-find-fast" control="findbar-textbox"/>
       <xul:textbox class="findbar-textbox findbar-find-fast" anonid="findbar-textbox"
                    xbl:inherits="flash"/>
-#ifdef MOZ_WIDGET_GTK2
+#ifdef MOZ_WIDGET_GTK
       <xul:toolbarbutton anonid="find-previous"
                          class="findbar-find-previous tabbable"
                          label="&previous.label;"
@@ -203,7 +203,7 @@
                          oncommand="onFindAgainCommand(false);"
                          disabled="true"
                          xbl:inherits="accesskey=findnextaccesskey"/>
-#ifndef MOZ_WIDGET_GTK2
+#ifndef MOZ_WIDGET_GTK
       <xul:toolbarbutton anonid="find-previous"
                          class="findbar-find-previous tabbable"
                          label="&previous.label;"
diff --git a/toolkit/content/widgets/tabbox.xml b/toolkit/content/widgets/tabbox.xml
index 26b97b29144..64b5cc11f58 100644
--- a/toolkit/content/widgets/tabbox.xml
+++ b/toolkit/content/widgets/tabbox.xml
@@ -577,7 +577,7 @@
       </method>
     </implementation>
 
-#ifdef MOZ_WIDGET_GTK2
+#ifdef MOZ_WIDGET_GTK
     <handlers>
       <handler event="DOMMouseScroll">
       <![CDATA[
diff --git a/toolkit/content/xul.css b/toolkit/content/xul.css
index 146b55143f9..3b50a3e1c00 100644
--- a/toolkit/content/xul.css
+++ b/toolkit/content/xul.css
@@ -140,7 +140,7 @@ button[type="menu-button"] {
   -moz-binding: url("chrome://global/content/bindings/button.xml#menu-button");
 }
 
-%ifdef MOZ_WIDGET_GTK2
+%ifdef MOZ_WIDGET_GTK
 /********* detection of system setting to use icons in buttons ***********/
 button[label]:not([label=""]) > .button-box > .button-icon:not(:-moz-system-metric(images-in-buttons)),
 button[label]:not([label=""]) > .button-box > .box-inherit > .button-icon:not(:-moz-system-metric(images-in-buttons)) {
@@ -368,7 +368,7 @@ menuitem.menuitem-non-iconic {
   -moz-binding: url("chrome://global/content/bindings/menu.xml#menubutton-item");
 }
 
-%ifdef MOZ_WIDGET_GTK2
+%ifdef MOZ_WIDGET_GTK
 /********* detection of system setting to use icons in menus ***********/
 @media not all and (-moz-images-in-menus) {
   .menu-iconic-left {
diff --git a/toolkit/library/nsStaticXULComponents.cpp b/toolkit/library/nsStaticXULComponents.cpp
index 4a2e7471cf1..4faaa232a11 100644
--- a/toolkit/library/nsStaticXULComponents.cpp
+++ b/toolkit/library/nsStaticXULComponents.cpp
@@ -36,7 +36,7 @@
 #  define WIDGET_MODULES MODULE(nsWidgetMacModule)
 #elif defined(XP_OS2)
 #  define WIDGET_MODULES MODULE(nsWidgetOS2Module)
-#elif defined(MOZ_WIDGET_GTK2)
+#elif defined(MOZ_WIDGET_GTK)
 #  define WIDGET_MODULES MODULE(nsWidgetGtk2Module)
 #elif defined(MOZ_WIDGET_QT)
 #  define WIDGET_MODULES MODULE(nsWidgetQtModule)
@@ -67,7 +67,7 @@
 #endif
 
 #ifdef MOZ_PREF_EXTENSIONS
-#ifdef MOZ_ENABLE_GTK2
+#ifdef MOZ_ENABLE_GTK
 #define SYSTEMPREF_MODULES \
     MODULE(nsAutoConfigModule)
 #else
@@ -125,7 +125,7 @@
 #endif
 
 #ifdef MOZ_XUL
-#ifdef MOZ_ENABLE_GTK2
+#ifdef MOZ_ENABLE_GTK
 #define UNIXPROXY_MODULE MODULE(nsUnixProxyModule)
 #endif
 #if defined(MOZ_WIDGET_QT)
diff --git a/toolkit/themes/winstripe/global/config.css b/toolkit/themes/winstripe/global/config.css
index b318d66c40c..98ce6abaabf 100644
--- a/toolkit/themes/winstripe/global/config.css
+++ b/toolkit/themes/winstripe/global/config.css
@@ -54,7 +54,7 @@
 
 #exclam
 {
-%ifdef MOZ_WIDGET_GTK2
+%ifdef MOZ_WIDGET_GTK
   list-style-image: url("moz-icon://stock/gtk-dialog-warning?size=dialog");
 %else
   list-style-image: url("chrome://global/skin/icons/warning-large.png");
diff --git a/toolkit/themes/winstripe/global/dirListing/dirListing.css b/toolkit/themes/winstripe/global/dirListing/dirListing.css
index 93e5820c5a8..a40bc50cd27 100644
--- a/toolkit/themes/winstripe/global/dirListing/dirListing.css
+++ b/toolkit/themes/winstripe/global/dirListing/dirListing.css
@@ -96,7 +96,7 @@ td:not(:first-child) {
   -moz-margin-end: 4px;
   -moz-margin-start: -20px;
   vertical-align: middle;
-%ifdef MOZ_WIDGET_GTK2
+%ifdef MOZ_WIDGET_GTK
   content: url(moz-icon://stock/gtk-go-up?size=menu);
 %else
   content: url(chrome://global/skin/dirListing/up.png);
@@ -104,7 +104,7 @@ td:not(:first-child) {
 }
 
 .dir::before {
-%ifdef MOZ_WIDGET_GTK2
+%ifdef MOZ_WIDGET_GTK
   content: url(moz-icon://stock/gtk-directory?size=menu);
 %else
   content: url(chrome://global/skin/dirListing/folder.png);
diff --git a/toolkit/xre/nsAppRunner.cpp b/toolkit/xre/nsAppRunner.cpp
index 9bb6715b15c..48b3823f94c 100644
--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -211,7 +211,7 @@ static int    gQtOnlyArgc;
 static char **gQtOnlyArgv;
 #endif
 
-#if defined(MOZ_WIDGET_GTK2)
+#if defined(MOZ_WIDGET_GTK)
 #if defined(DEBUG) || defined(NS_BUILD_REFCNT_LOGGING) \
   || defined(NS_TRACE_MALLOC)
 #define CLEANUP_MEMORY 1
@@ -2509,7 +2509,7 @@ public:
 };
 #endif
 
-#ifdef MOZ_WIDGET_GTK2
+#ifdef MOZ_WIDGET_GTK
 #include "prlink.h"
 typedef void (*_g_set_application_name_fn)(const gchar *application_name);
 typedef void (*_gtk_window_set_auto_startup_notification_fn)(gboolean setting);
@@ -2706,7 +2706,7 @@ public:
 #ifdef MOZ_ENABLE_XREMOTE
     , mDisableRemote(false)
 #endif
-#if defined(MOZ_WIDGET_GTK2)
+#if defined(MOZ_WIDGET_GTK)
     , mGdkDisplay(nsnull)
 #endif
   {};
@@ -2747,7 +2747,7 @@ public:
   bool mDisableRemote;
 #endif
 
-#if defined(MOZ_WIDGET_GTK2)
+#if defined(MOZ_WIDGET_GTK)
   GdkDisplay* mGdkDisplay;
 #endif
 };
@@ -3162,7 +3162,7 @@ XREMain::XRE_mainStartup(bool* aExitFlag)
     return 1;
   *aExitFlag = false;
 
-#if defined(MOZ_WIDGET_GTK2) || defined(MOZ_ENABLE_XREMOTE)
+#if defined(MOZ_WIDGET_GTK) || defined(MOZ_ENABLE_XREMOTE)
   // Stash DESKTOP_STARTUP_ID in malloc'ed memory because gtk_init will clear it.
 #define HAVE_DESKTOP_STARTUP_ID
   const char* desktopStartupIDEnv = PR_GetEnv("DESKTOP_STARTUP_ID");
@@ -3202,13 +3202,15 @@ XREMain::XRE_mainStartup(bool* aExitFlag)
   }
   gQtOnlyArgv[gQtOnlyArgc] = nsnull;
 #endif
-#if defined(MOZ_WIDGET_GTK2)
+#if defined(MOZ_WIDGET_GTK)
   // setup for private colormap.  Ideally we'd like to do this
   // in nsAppShell::Create, but we need to get in before gtk
   // has been initialized to make sure everything is running
   // consistently.
+#if (MOZ_WIDGET_GTK == 2)
   if (CheckArg("install"))
     gdk_rgb_set_install(TRUE);
+#endif
 
   // Initialize GTK here for splash.
 
@@ -3281,7 +3283,7 @@ XREMain::XRE_mainStartup(bool* aExitFlag)
     XInitThreads();
   }
 #endif
-#if defined(MOZ_WIDGET_GTK2)
+#if defined(MOZ_WIDGET_GTK)
   mGdkDisplay = gdk_display_open(display_name);
   if (!mGdkDisplay) {
     PR_fprintf(PR_STDERR, "Error: cannot open display: %s\n", display_name);
@@ -3302,8 +3304,10 @@ XREMain::XRE_mainStartup(bool* aExitFlag)
     _gtk_window_set_auto_startup_notification(false);
   }
 
+#if (MOZ_WIDGET_GTK == 2)
   gtk_widget_set_default_colormap(gdk_rgb_get_colormap());
-#endif /* MOZ_WIDGET_GTK2 */
+#endif /* (MOZ_WIDGET_GTK == 2) */
+#endif /* defined(MOZ_WIDGET_GTK) */
 #ifdef MOZ_X11
   // Do this after initializing GDK, or GDK will install its own handler.
   InstallX11ErrorHandler();
@@ -3324,7 +3328,7 @@ XREMain::XRE_mainStartup(bool* aExitFlag)
     return 1;
   }
 
-#if defined(HAVE_DESKTOP_STARTUP_ID) && defined(MOZ_WIDGET_GTK2)
+#if defined(HAVE_DESKTOP_STARTUP_ID) && defined(MOZ_WIDGET_GTK)
   // DESKTOP_STARTUP_ID is cleared now,
   // we recover it in case we need a restart.
   if (!mDesktopStartupID.IsEmpty()) {
@@ -3709,7 +3713,7 @@ XREMain::XRE_mainRun()
     rv = appStartup->CreateHiddenWindow();
     NS_ENSURE_SUCCESS(rv, 1);
 
-#if defined(HAVE_DESKTOP_STARTUP_ID) && defined(MOZ_WIDGET_GTK2)
+#if defined(HAVE_DESKTOP_STARTUP_ID) && defined(MOZ_WIDGET_GTK)
     nsGTKToolkit* toolkit = nsGTKToolkit::GetToolkit();
     if (toolkit && !mDesktopStartupID.IsEmpty()) {
       toolkit->SetDesktopStartupID(mDesktopStartupID);
@@ -3819,7 +3823,7 @@ XREMain::XRE_main(int argc, char* argv[], const nsXREAppData* aAppData)
 
   ScopedLogging log;
 
-#if defined(MOZ_WIDGET_GTK2)
+#if defined(MOZ_WIDGET_GTK)
 #ifdef MOZ_MEMORY
   // Disable the slice allocator, since jemalloc already uses similar layout
   // algorithms, and using a sub-allocator tends to increase fragmentation.
@@ -3898,7 +3902,7 @@ XREMain::XRE_main(int argc, char* argv[], const nsXREAppData* aAppData)
     SaveFileToEnvIfUnset("XRE_PROFILE_LOCAL_PATH", mProfLD);
     SaveWordToEnvIfUnset("XRE_PROFILE_NAME", mProfileName);
 
-#ifdef MOZ_WIDGET_GTK2
+#ifdef MOZ_WIDGET_GTK
     MOZ_gdk_display_close(mGdkDisplay);
 #endif
 
@@ -3911,7 +3915,7 @@ XREMain::XRE_main(int argc, char* argv[], const nsXREAppData* aAppData)
     return rv == NS_ERROR_LAUNCHED_CHILD_PROCESS ? 0 : 1;
   }
 
-#ifdef MOZ_WIDGET_GTK2
+#ifdef MOZ_WIDGET_GTK
   // gdk_display_close also calls gdk_display_manager_set_default_display
   // appropriately when necessary.
   MOZ_gdk_display_close(mGdkDisplay);
diff --git a/toolkit/xre/nsEmbedFunctions.cpp b/toolkit/xre/nsEmbedFunctions.cpp
index e0bc47abbf8..772fd098bad 100644
--- a/toolkit/xre/nsEmbedFunctions.cpp
+++ b/toolkit/xre/nsEmbedFunctions.cpp
@@ -11,7 +11,7 @@
 #include "nsXULAppAPI.h"
 
 #include <stdlib.h>
-#if defined(MOZ_WIDGET_GTK2)
+#if defined(MOZ_WIDGET_GTK)
 #include <glib.h>
 #endif
 
@@ -362,7 +362,7 @@ XRE_InitChildProcess(int aArgc,
   gArgv = aArgv;
   gArgc = aArgc;
 
-#if defined(MOZ_WIDGET_GTK2)
+#if defined(MOZ_WIDGET_GTK)
   g_thread_init(NULL);
 #endif
 
diff --git a/toolkit/xre/nsNativeAppSupportUnix.cpp b/toolkit/xre/nsNativeAppSupportUnix.cpp
index 0099fda7d4f..9b29bddf292 100644
--- a/toolkit/xre/nsNativeAppSupportUnix.cpp
+++ b/toolkit/xre/nsNativeAppSupportUnix.cpp
@@ -399,6 +399,7 @@ nsNativeAppSupportUnix::Start(bool *aRetVal)
 {
   NS_ASSERTION(gAppData, "gAppData must not be null.");
 
+#if (MOZ_WIDGET_GTK == 2)
   if (gtk_major_version < MIN_GTK_MAJOR_VERSION ||
       (gtk_major_version == MIN_GTK_MAJOR_VERSION && gtk_minor_version < MIN_GTK_MINOR_VERSION)) {
     GtkWidget* versionErrDialog = gtk_message_dialog_new(NULL,
@@ -415,6 +416,7 @@ nsNativeAppSupportUnix::Start(bool *aRetVal)
     gtk_widget_destroy(versionErrDialog);
     exit(0);
   }
+#endif
 
 #if (MOZ_PLATFORM_MAEMO == 5)
   /* zero state out. */
@@ -459,7 +461,7 @@ nsNativeAppSupportUnix::Start(bool *aRetVal)
 
   *aRetVal = true;
 
-#ifdef MOZ_X11
+#if defined(MOZ_X11) && (MOZ_WIDGET_GTK == 2)
 
   PRLibrary *gnomeuiLib = PR_LoadLibrary("libgnomeui-2.so.0");
   if (!gnomeuiLib)
@@ -482,7 +484,7 @@ nsNativeAppSupportUnix::Start(bool *aRetVal)
     return NS_OK;
   }
 
-#endif /* MOZ_X11 */
+#endif /* MOZ_X11 && (MOZ_WIDGET_GTK == 2) */
 
 #ifdef ACCESSIBILITY
   // We will load gail, atk-bridge by ourself later
@@ -493,11 +495,11 @@ nsNativeAppSupportUnix::Start(bool *aRetVal)
   setenv(accEnv, "0", 1);
 #endif
 
-#ifdef MOZ_X11
+#if defined(MOZ_X11) && (MOZ_WIDGET_GTK == 2)
   if (!gnome_program_get()) {
     gnome_program_init("Gecko", "1.0", libgnomeui_module_info_get(), gArgc, gArgv, NULL);
   }
-#endif /* MOZ_X11 */
+#endif /* MOZ_X11 && (MOZ_WIDGET_GTK == 2) */
 
 #ifdef ACCESSIBILITY
   if (accOldValue) { 
@@ -511,7 +513,8 @@ nsNativeAppSupportUnix::Start(bool *aRetVal)
   // gnome_program_init causes atexit handlers to be registered. Strange
   // crashes will occur if these libraries are unloaded.
 
-#ifdef MOZ_X11
+  // TODO GTK3 - see Bug 694570 - Stop using libgnome and libgnomeui on Linux
+#if defined(MOZ_X11) && (MOZ_WIDGET_GTK == 2)
   gnome_client_set_restart_command = (_gnome_client_set_restart_command_fn)
     PR_FindFunctionSymbol(gnomeuiLib, "gnome_client_set_restart_command");
 
@@ -554,7 +557,7 @@ nsNativeAppSupportUnix::Start(bool *aRetVal)
   if (argv1) {
     gnome_client_set_restart_command(client, 1, &argv1);
   }
-#endif /* MOZ_X11 */
+#endif /* MOZ_X11 && (MOZ_WIDGET_GTK == 2) */
 
   return NS_OK;
 }
diff --git a/toolkit/xre/nsSigHandlers.cpp b/toolkit/xre/nsSigHandlers.cpp
index 3a425dc1348..74ddeb9122c 100644
--- a/toolkit/xre/nsSigHandlers.cpp
+++ b/toolkit/xre/nsSigHandlers.cpp
@@ -101,12 +101,12 @@ child_ah_crap_handler(int signum)
 
 #endif // CRAWL_STACK_ON_SIGSEGV
 
-#ifdef MOZ_WIDGET_GTK2
+#ifdef MOZ_WIDGET_GTK
 // Need this include for version test below.
 #include <glib.h>
 #endif
 
-#if defined(MOZ_WIDGET_GTK2) && (GLIB_MAJOR_VERSION > 2 || (GLIB_MAJOR_VERSION == 2 && GLIB_MINOR_VERSION >= 6))
+#if defined(MOZ_WIDGET_GTK) && (GLIB_MAJOR_VERSION > 2 || (GLIB_MAJOR_VERSION == 2 && GLIB_MINOR_VERSION >= 6))
 
 static GLogFunc orig_log_func = NULL;
 
@@ -282,7 +282,7 @@ void InstallSignalHandlers(const char *ProgramName)
     }
 #endif //SOLARIS
 
-#if defined(MOZ_WIDGET_GTK2) && (GLIB_MAJOR_VERSION > 2 || (GLIB_MAJOR_VERSION == 2 && GLIB_MINOR_VERSION >= 6))
+#if defined(MOZ_WIDGET_GTK) && (GLIB_MAJOR_VERSION > 2 || (GLIB_MAJOR_VERSION == 2 && GLIB_MINOR_VERSION >= 6))
   const char *assertString = PR_GetEnv("XPCOM_DEBUG_BREAK");
   if (assertString &&
       (!strcmp(assertString, "suspend") ||