diff --git a/vpn_service.h b/vpn_service.h
index 5f9a0b1..02c0870 100644
--- a/vpn_service.h
+++ b/vpn_service.h
@@ -25,7 +25,7 @@
              Metrics *metrics,
              Manager *manager,
              VPNDriver *driver);  // Takes ownership of |driver|.
-  virtual ~VPNService();
+  ~VPNService() override;
 
   // Inherited from Service.
   virtual void Connect(Error *error, const char *reason);