diff --git a/libcxx/utils/generate_iwyu_mapping.py b/libcxx/utils/generate_iwyu_mapping.py
index 599201808bb79..6946cd2a612f4 100644
--- a/libcxx/utils/generate_iwyu_mapping.py
+++ b/libcxx/utils/generate_iwyu_mapping.py
@@ -15,6 +15,7 @@ def IWYU_mapping(header: str) -> typing.Optional[typing.List[str]]:
         "__pstl/.+",
         "__support/.+",
         "__utility/private_constructor_tag.h",
+        "__cxx03/.+",  # FIXME: Workaround for https://github.com/llvm/llvm-project/pull/108999
     ]
     if any(re.match(pattern, header) for pattern in ignore):
         return None