diff --git a/nix-darwin/default.nix b/nix-darwin/default.nix
index 9947ff855976..c529ca4a1020 100644
--- a/nix-darwin/default.nix
+++ b/nix-darwin/default.nix
@@ -12,7 +12,7 @@ let
     specialArgs = { 
       lib = extendedLib; 
       darwinConfig = config;
-    };
+    } // cfg.extraSpecialArgs;
     modules = [
       ({ name, ... }: {
         imports = import ../modules/modules.nix {
@@ -29,7 +29,7 @@ let
           home.homeDirectory = config.users.users.${name}.home;
         };
       })
-    ];
+    ] ++ cfg.sharedModules;
   };
 
 in
@@ -58,6 +58,24 @@ in
         '';
       };
 
+      extraSpecialArgs = mkOption {
+        type = types.attrs;
+        default = { };
+        example = literalExample "{ modulesPath = ../modules; }";
+        description = ''
+          Extra <literal>specialArgs</literal> passed to Home Manager.
+        '';
+      };
+
+      sharedModules = mkOption {
+        type = with types; listOf (oneOf [ attrs (functionTo attrs) path ]);
+        default = [ ];
+        example = literalExample "[ { home.packages = [ nixpkgs-fmt ]; } ]";
+        description = ''
+          Extra modules added to all users.
+        '';
+      };
+
       verbose = mkEnableOption "verbose output on activation";
 
       users = mkOption {