diff --git a/modules/system/defaults/dock.nix b/modules/system/defaults/dock.nix
index bba0afb..8eaf5ca 100644
--- a/modules/system/defaults/dock.nix
+++ b/modules/system/defaults/dock.nix
@@ -134,10 +134,14 @@ in {
       description = ''
         Persistent applications in the dock.
       '';
-      apply = value:
-        if !(isList value)
-        then value
-        else map (app: { tile-data = { file-data = { _CFURLString = app; _CFURLStringType = 0; }; }; }) value;
+      apply =
+      let
+        tileTypes = ["spacer-tile" "small-spacer-tile"];
+        toSpecialTile = type: { tile-data = {}; tile-type = type; };
+        toAppTile = cfurl: { tile-data = { file-data = { _CFURLString = cfurl; _CFURLStringType = 0; }; }; };
+        toTile = s: if elem s tileTypes then toSpecialTile s else toAppTile s;
+      in
+      value: if isList value then map toTile value else value;
     };
 
     system.defaults.dock.persistent-others = mkOption {
diff --git a/tests/fixtures/system-defaults-write/activate-user.txt b/tests/fixtures/system-defaults-write/activate-user.txt
index eda3753..aa60500 100644
--- a/tests/fixtures/system-defaults-write/activate-user.txt
+++ b/tests/fixtures/system-defaults-write/activate-user.txt
@@ -273,6 +273,22 @@ defaults write com.apple.dock 'persistent-apps' $'<?xml version="1.0" encoding="
 			</dict>
 		</dict>
 	</dict>
+	<dict>
+		<key>tile-data</key>
+		<dict>
+
+		</dict>
+		<key>tile-type</key>
+		<string>small-spacer-tile</string>
+	</dict>
+	<dict>
+		<key>tile-data</key>
+		<dict>
+
+		</dict>
+		<key>tile-type</key>
+		<string>spacer-tile</string>
+	</dict>
 </array>
 </plist>'
 defaults write com.apple.dock 'persistent-others' $'<?xml version="1.0" encoding="UTF-8"?>
diff --git a/tests/system-defaults-write.nix b/tests/system-defaults-write.nix
index 0b8bc03..3f69c0b 100644
--- a/tests/system-defaults-write.nix
+++ b/tests/system-defaults-write.nix
@@ -50,7 +50,7 @@
   system.defaults.dock.appswitcher-all-displays = false;
   system.defaults.dock.autohide-delay = 0.24;
   system.defaults.dock.orientation = "left";
-  system.defaults.dock.persistent-apps = ["MyApp.app" "Cool.app"];
+  system.defaults.dock.persistent-apps = ["MyApp.app" "Cool.app" "small-spacer-tile" "spacer-tile"];
   system.defaults.dock.persistent-others = ["~/Documents" "~/Downloads/file.txt"];
   system.defaults.dock.scroll-to-open = false;
   system.defaults.finder.AppleShowAllFiles = true;