diff --git a/build/config/BUILD.gn b/build/config/BUILD.gn
index e313d21a164fe..e49a24bc23ef4 100644
--- a/build/config/BUILD.gn
+++ b/build/config/BUILD.gn
@@ -136,7 +136,7 @@ config("feature_flags") {
   if (use_allocator != "tcmalloc") {
     defines += [ "NO_TCMALLOC" ]
   }
-  if (is_asan || is_lsan || is_tsan || is_msan) {
+  if (is_asan || is_lsan || is_tsan || is_msan || is_ios) {
     defines += [
       "MEMORY_TOOL_REPLACES_ALLOCATOR",
       "MEMORY_SANITIZER_INITIAL_SIZE",