diff --git a/modules/applications/default.nix b/modules/applications/default.nix
index 8b91151..3ad5179 100644
--- a/modules/applications/default.nix
+++ b/modules/applications/default.nix
@@ -14,6 +14,7 @@
     ./git
     ./gnupg
     ./grok.nix
+    ./gnome.nix
     ./greetd.nix
     ./ly
     ./gtk
diff --git a/modules/applications/gnome.nix b/modules/applications/gnome.nix
new file mode 100644
index 0000000..c482c36
--- /dev/null
+++ b/modules/applications/gnome.nix
@@ -0,0 +1,26 @@
+{
+  pkgs,
+  lib,
+  config,
+  ...
+}:
+let
+  cfg = config.my.applications.gnome;
+in
+{
+  options.my.applications.gnome = {
+    enable = lib.mkEnableOption "GNOME desktop environment";
+  };
+
+  config = lib.mkIf cfg.enable {
+    services.desktopManager.gnome.enable = true;
+
+    # ly is the display manager for switching between installed sessions.
+    services.displayManager.gdm.enable = lib.mkForce false;
+
+    environment.systemPackages = with pkgs; [
+      gnome-tweaks # GNOME desktop customization tool
+      gnome-extension-manager # GNOME Shell extension manager
+    ];
+  };
+}
diff --git a/modules/applications/ly/default.nix b/modules/applications/ly/default.nix
index 4904570..bdae7a2 100644
--- a/modules/applications/ly/default.nix
+++ b/modules/applications/ly/default.nix
@@ -17,6 +17,8 @@ in
   };
 
   config = lib.mkIf cfg.enable {
+    services.displayManager.defaultSession = lib.mkDefault "niri";
+
     services.displayManager.ly = {
       enable = true;
       settings = {
diff --git a/modules/applications/wayland.nix b/modules/applications/wayland.nix
index e702877..0d400e5 100644
--- a/modules/applications/wayland.nix
+++ b/modules/applications/wayland.nix
@@ -15,19 +15,27 @@ in
   config = lib.mkIf cfg.enable {
     programs.xwayland.enable = true;
 
+    # Keep global Wayland portal settings in this module so hardware/application
+    # modules do not each append their own portal backends.
     xdg.portal = {
       enable = true;
       wlr.enable = true;
       extraPortals = [
-        pkgs.xdg-desktop-portal-wlr
+        pkgs.xdg-desktop-portal-gnome
         pkgs.xdg-desktop-portal-gtk
+        pkgs.xdg-desktop-portal-wlr
       ];
       xdgOpenUsePortal = true;
       config = {
-        common.default = [
+        common.default = [ "gtk" ];
+        niri.default = [
           "wlr"
           "gtk"
         ];
+        gnome.default = [
+          "gnome"
+          "gtk"
+        ];
       };
     };
 
diff --git a/modules/features/gui/desktop.nix b/modules/features/gui/desktop.nix
index 4dd3f49..a5c060f 100644
--- a/modules/features/gui/desktop.nix
+++ b/modules/features/gui/desktop.nix
@@ -8,11 +8,12 @@ let
 in
 {
   options.my.features.gui.desktop = {
-    enable = lib.mkEnableOption "Niri Wayland compositor environment";
+    enable = lib.mkEnableOption "Graphical desktop sessions";
   };
 
   config = lib.mkIf cfg.enable {
     my.applications = {
+      gnome.enable = true;
       gtk.enable = true;
       niri.enable = true;
       wayland.enable = true;
diff --git a/modules/system/camera.nix b/modules/system/camera.nix
index 08ff67a..c2dd31b 100644
--- a/modules/system/camera.nix
+++ b/modules/system/camera.nix
@@ -32,10 +32,5 @@ in
       pulse.enable = true;
     };
     security.rtkit.enable = true;
-
-    xdg.portal = {
-      enable = true;
-      extraPortals = [ pkgs.xdg-desktop-portal-gtk ];
-    };
   };
 }