diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index 5b17b838e343..96b117c3f9e5 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -1585,6 +1585,7 @@ in
   sx = runTest ./sx.nix;
   sympa = runTest ./sympa.nix;
   syncthing = runTest ./syncthing/main.nix;
+  syncthing-defaults = runTest ./syncthing/defaults.nix;
   syncthing-folders = runTest ./syncthing/folders.nix;
   syncthing-guiPassword = runTest ./syncthing/guiPassword.nix;
   syncthing-guiPasswordFile = runTest ./syncthing/guiPasswordFile.nix;
diff --git a/nixos/tests/syncthing/defaults.nix b/nixos/tests/syncthing/defaults.nix
new file mode 100644
index 000000000000..cd90d40770e5
--- /dev/null
+++ b/nixos/tests/syncthing/defaults.nix
@@ -0,0 +1,42 @@
+{ lib, pkgs, ... }:
+let
+  expectedPath = "/tmp/syncthing-default";
+in
+{
+  name = "syncthing-defaults";
+  meta.maintainers = with pkgs.lib.maintainers; [ seudonym ];
+
+  nodes.machine =
+    { pkgs, ... }:
+    {
+      environment.systemPackages = [
+        pkgs.libxml2
+        pkgs.curl
+      ];
+      services.syncthing = {
+        enable = true;
+        settings.defaults.folder.path = expectedPath;
+      };
+    };
+
+  testScript = ''
+    import json
+
+    machine.wait_for_unit("syncthing.service")
+    machine.wait_for_unit("syncthing-init.service")
+
+    # Get the API key by parsing the config.xml
+    api_key = machine.succeed(
+        "xmllint --xpath 'string(configuration/gui/apikey)' /var/lib/syncthing/.config/syncthing/config.xml"
+    ).strip()
+
+    # Query the defaults/folder endpoint via Syncthing's REST API
+    config = json.loads(machine.succeed(
+        f"curl -Ssf -H 'X-API-Key: {api_key}' http://127.0.0.1:8384/rest/config/defaults/folder"
+    ))
+
+    actual_path = config.get('path')
+    assert actual_path == "${expectedPath}", f"Default folder path is '{actual_path}', but expected '${expectedPath}'"
+    machine.log(f"Success: Default folder path is correctly set to '{actual_path}'")
+  '';
+}