diff --git a/modules/misc/gtk/gtk4.nix b/modules/misc/gtk/gtk4.nix
index 9d71f76e..98a7e818 100644
--- a/modules/misc/gtk/gtk4.nix
+++ b/modules/misc/gtk/gtk4.nix
@@ -45,8 +45,24 @@ in
           packageExample = "pkgs.gnome.gnome-themes-extra";
         }
       );
-      default = if lib.versionOlder config.home.stateVersion "26.05" then cfg.theme else null;
-      defaultText = literalExpression ''if lib.versionOlder config.home.stateVersion "26.05" then cfg.theme else null'';
+      inherit
+        (lib.hm.deprecations.mkStateVersionOptionDefault {
+          inherit (config.home) stateVersion;
+          since = "26.05";
+          optionPath = [
+            "gtk"
+            "gtk4"
+            "theme"
+          ];
+          legacy = {
+            value = cfg.theme;
+            text = "config.gtk.theme";
+          };
+          current.value = null;
+        })
+        default
+        defaultText
+        ;
       description = ''
         Theme for GTK 4 applications.
 
diff --git a/tests/modules/misc/gtk/default.nix b/tests/modules/misc/gtk/default.nix
index 69a77242..c206173e 100644
--- a/tests/modules/misc/gtk/default.nix
+++ b/tests/modules/misc/gtk/default.nix
@@ -15,6 +15,7 @@
 
   # GTK4
   gtk4-basic-settings = ./gtk4/gtk4-basic-settings.nix;
+  gtk4-stateversion-theme-inheritance = ./gtk4/gtk4-stateversion-theme-inheritance.nix;
   gtk4-theme-css-injection = ./gtk4/gtk4-theme-css-injection.nix;
   gtk4-no-theme-css-injection = ./gtk4/gtk4-no-theme-css-injection.nix;
   gtk4-stateversion-no-theme-inheritance = ./gtk4/gtk4-stateversion-no-theme-inheritance.nix;
diff --git a/tests/modules/misc/gtk/gtk4/gtk4-stateversion-theme-inheritance.nix b/tests/modules/misc/gtk/gtk4/gtk4-stateversion-theme-inheritance.nix
new file mode 100644
index 00000000..785d48bd
--- /dev/null
+++ b/tests/modules/misc/gtk/gtk4/gtk4-stateversion-theme-inheritance.nix
@@ -0,0 +1,19 @@
+{ pkgs, ... }:
+{
+  home.stateVersion = "25.11";
+
+  gtk = {
+    enable = true;
+    theme = {
+      name = "Adwaita-dark";
+      package = pkgs.gnome-themes-extra;
+    };
+  };
+
+  nmt.script = ''
+    assertFileRegex home-files/.config/gtk-4.0/settings.ini \
+      '^gtk-theme-name=Adwaita-dark$'
+    assertFileContains home-files/.config/gtk-4.0/gtk.css \
+      'share/themes/Adwaita-dark/gtk-4.0/gtk.css'
+  '';
+}