diff --git a/nixos/modules/services/networking/openvpn.nix b/nixos/modules/services/networking/openvpn.nix
index fba6d5e48f92..d122390c88ca 100644
--- a/nixos/modules/services/networking/openvpn.nix
+++ b/nixos/modules/services/networking/openvpn.nix
@@ -64,7 +64,7 @@ let
 
       path = [ pkgs.iptables pkgs.iproute2 pkgs.nettools ];
 
-      serviceConfig.ExecStart = "@${openvpn}/sbin/openvpn openvpn --suppress-timestamps --config ${configFile}";
+      serviceConfig.ExecStart = "@${openvpn}/sbin/openvpn openvpn --suppress-timestamps --config ${configFile} ${cfg.extraArgs}";
       serviceConfig.Restart = "always";
       serviceConfig.Type = "notify";
     };
@@ -181,6 +181,15 @@ in
             '';
           };
 
+          extraArgs = mkOption {
+            default = null;
+            type = listOf str;
+            description = ''
+              Additional command line arguments to pass to this OpenVPN instance.
+            '';
+            apply = lib.escapeShellArgs;
+          };
+
           authUserPass = mkOption {
             default = null;
             description = ''