diff --git a/widget/gtk/nsGtkKeyUtils.h b/widget/gtk/nsGtkKeyUtils.h
--- a/widget/gtk/nsGtkKeyUtils.h
+++ b/widget/gtk/nsGtkKeyUtils.h
@@ -169,17 +169,20 @@ protected:
 
     bool mInitialized;
 
     /**
      * Initializing methods.
      */
     void Init();
     void InitXKBExtension();
-    void InitBySystemSettings();
+    void InitBySystemSettingsX11();
+#ifdef MOZ_WAYLAND
+    void InitBySystemSettingsWayland();
+#endif
 
     /**
      * mModifierKeys stores each hardware key information.
      */
     struct ModifierKey {
         guint mHardwareKeycode;
         guint mMask;
 

diff --git a/widget/gtk/nsGtkKeyUtils.cpp b/widget/gtk/nsGtkKeyUtils.cpp
--- a/widget/gtk/nsGtkKeyUtils.cpp
+++ b/widget/gtk/nsGtkKeyUtils.cpp
@@ -190,17 +190,21 @@ KeymapWrapper::Init()
     MOZ_LOG(gKeymapWrapperLog, LogLevel::Info,
         ("%p Init, mGdkKeymap=%p",
          this, mGdkKeymap));
 
     mModifierKeys.Clear();
     memset(mModifierMasks, 0, sizeof(mModifierMasks));
 
     if (GDK_IS_X11_DISPLAY(gdk_display_get_default()))
-        InitBySystemSettings();
+        InitBySystemSettingsX11();
+#ifdef MOZ_WAYLAND
+    else
+        InitBySystemSettingsWayland();
+#endif
 
     gdk_window_add_filter(nullptr, FilterEvents, this);
 
     MOZ_LOG(gKeymapWrapperLog, LogLevel::Info,
         ("%p Init, CapsLock=0x%X, NumLock=0x%X, "
          "ScrollLock=0x%X, Level3=0x%X, Level5=0x%X, "
          "Shift=0x%X, Ctrl=0x%X, Alt=0x%X, Meta=0x%X, Super=0x%X, Hyper=0x%X",
          this,
@@ -270,20 +274,20 @@ KeymapWrapper::InitXKBExtension()
         return;
     }
 
     MOZ_LOG(gKeymapWrapperLog, LogLevel::Info,
         ("%p InitXKBExtension, Succeeded", this));
 }
 
 void
-KeymapWrapper::InitBySystemSettings()
+KeymapWrapper::InitBySystemSettingsX11()
 {
     MOZ_LOG(gKeymapWrapperLog, LogLevel::Info,
-        ("%p InitBySystemSettings, mGdkKeymap=%p",
+        ("%p InitBySystemSettingsX11, mGdkKeymap=%p",
          this, mGdkKeymap));
 
     Display* display =
         gdk_x11_display_get_xdisplay(gdk_display_get_default());
 
     int min_keycode = 0;
     int max_keycode = 0;
     XDisplayKeycodes(display, &min_keycode, &max_keycode);
@@ -434,16 +438,26 @@ KeymapWrapper::InitBySystemSettings()
             }
         }
     }
 
     XFreeModifiermap(xmodmap);
     XFree(xkeymap);
 }
 
+#ifdef MOZ_WAYLAND
+void
+KeymapWrapper::InitBySystemSettingsWayland()
+{
+    // Not implemented yet, but at least Alt modifier should be handled to save
+    // popular usage.
+    mModifierMasks[INDEX_ALT] = 1 << 3;
+}
+#endif
+
 KeymapWrapper::~KeymapWrapper()
 {
     gdk_window_remove_filter(nullptr, FilterEvents, this);
     g_signal_handlers_disconnect_by_func(mGdkKeymap,
                                          FuncToGpointer(OnKeysChanged), this);
     g_signal_handlers_disconnect_by_func(mGdkKeymap,
                                          FuncToGpointer(OnDirectionChanged), this);
     g_object_unref(mGdkKeymap);