diff --git a/zircon/system/utest/core/stack/BUILD.gn b/zircon/system/utest/core/stack/BUILD.gn
index 494286c3f239cc579a98f0a21cb65a6d3f7163d5..7f56004515364c45cf40805fea3ca53a949dd761 100644
--- a/zircon/system/utest/core/stack/BUILD.gn
+++ b/zircon/system/utest/core/stack/BUILD.gn
@@ -5,7 +5,7 @@
 source_set("stack") {
   testonly = true
   sources = [
-    "stack-test.c",
+    "stack-test.cpp",
   ]
   cflags = [ "-fstack-protector-all" ]
   deps = [
diff --git a/zircon/system/utest/core/stack/stack-test.c b/zircon/system/utest/core/stack/stack-test.cpp
similarity index 100%
rename from zircon/system/utest/core/stack/stack-test.c
rename to zircon/system/utest/core/stack/stack-test.cpp