diff --git a/cores/arduino/new.cpp b/cores/arduino/new.cpp
index 7ca493169..fd5e0d1fb 100644
--- a/cores/arduino/new.cpp
+++ b/cores/arduino/new.cpp
@@ -92,10 +92,10 @@ void operator delete[](void * ptr) noexcept {
 }
 
 #if __cplusplus >= 201402L
-void operator delete(void* ptr, std::size_t size) noexcept {
+void operator delete(void* ptr, [[gnu::unused]] std::size_t size) noexcept {
   operator delete(ptr);
 }
-void operator delete[](void * ptr, std::size_t size) noexcept {
+void operator delete[](void * ptr, [[gnu::unused]] std::size_t size) noexcept {
   operator delete[](ptr);
 }
 #endif // __cplusplus >= 201402L