diff --git a/include/stddef.h b/include/stddef.h
index bb4f585b..bd2d5b2b 100644
--- a/include/stddef.h
+++ b/include/stddef.h
@@ -17,7 +17,10 @@ typedef union { long long __ll; long double __ld; } max_align_t;
 typedef signed char int8_t;
 typedef signed short int int16_t;
 typedef signed int int32_t;
-#if defined(__LP64__) && !defined(__APPLE__) && !defined(__OpenBSD__)
+#if defined(__LP64__) \
+  && !defined(__APPLE__) \
+  && !defined(__OpenBSD__) \
+  && !(defined(__NetBSD__) && defined(__aarch64__))
 typedef signed long int int64_t;
 #else
 typedef signed long long int int64_t;
@@ -25,7 +28,10 @@ typedef signed long long int int64_t;
 typedef unsigned char uint8_t;
 typedef unsigned short int uint16_t;
 typedef unsigned int uint32_t;
-#if defined(__LP64__) && !defined(__APPLE__) && !defined(__OpenBSD__)
+#if defined(__LP64__) \
+  && !defined(__APPLE__) \
+  && !defined(__OpenBSD__) \
+  && !(defined(__NetBSD__) && defined(__aarch64__))
 typedef unsigned long int uint64_t;
 #else
 typedef unsigned long long int uint64_t;