diff --git a/nixos/vm/config.nix b/nixos/vm/config.nix
index f521cd0..0aeaf3d 100644
--- a/nixos/vm/config.nix
+++ b/nixos/vm/config.nix
@@ -29,7 +29,7 @@ let
         '';
       };
 
-      mkMacvtap = macvtapName: macvtapCfg:
+      mkMacvtap = macvtapName: macvtapVmCfg:
       let
         macvtapNetworkCfg = config.vmix.networks.${netCfg.name}.bridges.macvtaps.${macvtapName};
         macvtapInterfaceName = "mt-${vmCfg.name}-${macvtapNetworkCfg.uplink.iface}";
@@ -37,9 +37,10 @@ let
       {
         name = macvtapName;
         iface = macvtapInterfaceName;
-        mac = macvtapCfg.mac;
+        mac = macvtapVmCfg.mac;
         create = ''
           ip link add link ${macvtapNetworkCfg.uplink.iface} name ${macvtapInterfaceName} type macvtap mode bridge
+          ${lib.optionalString (macvtapVmCfg.mac != null) "ip link set dev ${macvtapInterfaceName} address ${macvtapVmCfg.mac}"}
           ip link set ${macvtapInterfaceName} netns ${netName}.vmix
           ip netns exec ${netName}.vmix ip link set dev ${macvtapInterfaceName} up
         '';
diff --git a/nixos/vm/options.nix b/nixos/vm/options.nix
index 6a982a9..4055bde 100644
--- a/nixos/vm/options.nix
+++ b/nixos/vm/options.nix
@@ -151,7 +151,8 @@ with lib;
                   description = "Enable the MACVTap interface.";
                 };
                 mac = mkOption {
-                  type = types.str;
+                  type = types.nullOr types.str;
+                  default = null;
                   description = "MAC address for the MACVTap interface.";
                 };
               };