diff --git a/src/lib/spinel/radio_spinel.hpp b/src/lib/spinel/radio_spinel.hpp
index 2096b720d..8fdca562e 100644
--- a/src/lib/spinel/radio_spinel.hpp
+++ b/src/lib/spinel/radio_spinel.hpp
@@ -1066,7 +1066,7 @@ public:
      *
      */
     void SetVendorRestorePropertiesCallback(otRadioSpinelVendorRestorePropertiesCallback aCallback, void *aContext);
-#endif
+#endif // OPENTHREAD_SPINEL_CONFIG_VENDOR_HOOK_ENABLE
 
 private:
     enum