diff --git a/libc/private/bionic_macros.h b/libc/private/bionic_macros.h
index 979a704..0a36cdb 100644
--- a/libc/private/bionic_macros.h
+++ b/libc/private/bionic_macros.h
@@ -94,4 +94,12 @@
 
 #define arraysize(array) (sizeof(ArraySizeHelper(array)))
 
+// Used to inform clang's -Wimplicit-fallthrough that a fallthrough is intended. There's no way to
+// silence (or enable, apparently) -Wimplicit-fallthrough in C yet.
+#ifdef __cplusplus
+#define __BIONIC_FALLTHROUGH [[clang::fallthrough]]
+#else
+#define __BIONIC_FALLTHROUGH
+#endif
+
 #endif // _BIONIC_MACROS_H_