diff --git a/tests/lib/cpp/cxx/src/main.cpp b/tests/lib/cpp/cxx/src/main.cpp
index 8b149290bab..1f6864a3375 100644
--- a/tests/lib/cpp/cxx/src/main.cpp
+++ b/tests/lib/cpp/cxx/src/main.cpp
@@ -99,7 +99,7 @@ struct foo {
 /* Check that BUILD_ASSERT compiles. */
 BUILD_ASSERT(sizeof(foo) == sizeof(int));
 
-static struct foo foos[5];
+__maybe_unused static struct foo foos[5];
 /* Check that ARRAY_SIZE compiles. */
 BUILD_ASSERT(ARRAY_SIZE(foos) == 5, "expected 5 elements");