diff --git a/pw_string/string_builder_test.cc b/pw_string/string_builder_test.cc
index ee8bad5..c3bc3b0 100644
--- a/pw_string/string_builder_test.cc
+++ b/pw_string/string_builder_test.cc
@@ -521,10 +521,11 @@
 TEST(MakeString, StringLiteral_ResizesToFitWholeLiteral) {
   EXPECT_STREQ("", MakeString().data());
 
-  auto normal = MakeString("");
+  [[maybe_unused]] auto normal = MakeString("");
   static_assert(normal.max_size() == decltype(MakeString(1))::max_size());
 
-  auto resized = MakeString("This string is reeeeeeeeeaaaaallly long!!!!!");
+  [[maybe_unused]] auto resized =
+      MakeString("This string is reeeeeeeeeaaaaallly long!!!!!");
   static_assert(resized.max_size() > decltype(MakeString(1))::max_size());
   static_assert(resized.max_size() ==
                 sizeof("This string is reeeeeeeeeaaaaallly long!!!!!") - 1);