diff --git a/include/sys/cbprintf_cxx.h b/include/sys/cbprintf_cxx.h
index 692618a678f..4e602a528e3 100644
--- a/include/sys/cbprintf_cxx.h
+++ b/include/sys/cbprintf_cxx.h
@@ -57,6 +57,7 @@ static inline int z_cbprintf_cxx_is_pchar(const volatile wchar_t *, bool const_a
 template < typename T >
 static inline int z_cbprintf_cxx_is_pchar(T arg, bool const_as_fixed)
 {
+	ARG_UNUSED(arg);
 	_Pragma("GCC diagnostic push")
 	_Pragma("GCC diagnostic ignored \"-Wpointer-arith\"")
 	ARG_UNUSED(const_as_fixed);