diff --git a/libcxx/test/libcxx/xopen_source.gen.py b/libcxx/test/libcxx/xopen_source.gen.py
index 3f2686483730a..d4a3651181ca7 100644
--- a/libcxx/test/libcxx/xopen_source.gen.py
+++ b/libcxx/test/libcxx/xopen_source.gen.py
@@ -43,6 +43,9 @@
 // recent value of _XOPEN_SOURCE.
 // UNSUPPORTED: LIBCXX-AIX-FIXME
 
+// This test fails on FreeBSD for an unknown reason.
+// UNSUPPORTED: LIBCXX-FREEBSD-FIXME
+
 {lit_header_restrictions.get(header, '')}
 {lit_header_undeprecations.get(header, '')}