diff --git a/Libraries/LibC/stdint.h b/Libraries/LibC/stdint.h
index 8dfe120712..8e1fbcba4d 100644
--- a/Libraries/LibC/stdint.h
+++ b/Libraries/LibC/stdint.h
@@ -104,4 +104,6 @@ typedef __INTMAX_TYPE__ intmax_t;
 #define INT64_C(x) x##LL
 #define UINT64_C(x) x##ULL
 
+#define SIZE_MAX ((size_t)-1)
+
 __END_DECLS