diff --git a/nixos/modules/services/x11/display-managers/lightdm.nix b/nixos/modules/services/x11/display-managers/lightdm.nix
index 3ab4f26399f3..afa0cebbc527 100644
--- a/nixos/modules/services/x11/display-managers/lightdm.nix
+++ b/nixos/modules/services/x11/display-managers/lightdm.nix
@@ -189,6 +189,11 @@ in
   config = mkIf cfg.enable {
 
     assertions = [
+      { assertion = xcfg.enable;
+        message = ''
+          LightDM requires services.xserver.enable to be true
+        '';
+      }
       { assertion = cfg.autoLogin.enable -> cfg.autoLogin.user != null;
         message = ''
           LightDM auto-login requires services.xserver.displayManager.lightdm.autoLogin.user to be set
diff --git a/nixos/modules/services/x11/display-managers/sddm.nix b/nixos/modules/services/x11/display-managers/sddm.nix
index 05830e325d51..d1ed345ac579 100644
--- a/nixos/modules/services/x11/display-managers/sddm.nix
+++ b/nixos/modules/services/x11/display-managers/sddm.nix
@@ -195,6 +195,11 @@ in
   config = mkIf cfg.enable {
 
     assertions = [
+      { assertion = xcfg.enable;
+        message = ''
+          SDDM requires services.xserver.enable to be true
+        '';
+      }
       { assertion = cfg.autoLogin.enable -> cfg.autoLogin.user != null;
         message = ''
           SDDM auto-login requires services.xserver.displayManager.sddm.autoLogin.user to be set
@@ -264,8 +269,8 @@ in
     };
 
     environment.etc."sddm.conf".source = cfgFile;
-    environment.pathsToLink = [ 
-      "/share/sddm" 
+    environment.pathsToLink = [
+      "/share/sddm"
     ];
 
     users.groups.sddm.gid = config.ids.gids.sddm;