diff --git a/lib/libspl/include/sys/feature_tests.h b/lib/libspl/include/sys/feature_tests.h
index a36fd7b8cffb..c9564b2c3269 100644
--- a/lib/libspl/include/sys/feature_tests.h
+++ b/lib/libspl/include/sys/feature_tests.h
@@ -30,7 +30,7 @@
 #define	____cacheline_aligned
 #define	__NORETURN		__attribute__((__noreturn__))
 
-#if !defined(fallthrough)
+#if !defined(fallthrough) && !defined(_LIBCPP_VERSION)
 #if defined(HAVE_IMPLICIT_FALLTHROUGH)
 #define	fallthrough		__attribute__((__fallthrough__))
 #else