diff --git a/port/port_posix.h b/port/port_posix.h
index 1234567..abcdefg 100644
--- a/port/port_posix.h
+++ b/port/port_posix.h
@@ -58,6 +58,15 @@
 #include <limits>
 #include <string>
 
+// iOS/macOS endianness detection
+#if defined(__APPLE__)
+#include <machine/endian.h>
+#if !defined(__BYTE_ORDER) && defined(BYTE_ORDER)
+#define __BYTE_ORDER BYTE_ORDER
+#define __LITTLE_ENDIAN LITTLE_ENDIAN
+#endif
+#endif
+
 #ifndef PLATFORM_IS_LITTLE_ENDIAN
 #define PLATFORM_IS_LITTLE_ENDIAN (__BYTE_ORDER == __LITTLE_ENDIAN)
 #endif
@@ -65,7 +74,7 @@
 
 #if defined(OS_MACOSX) || defined(OS_SOLARIS) || defined(OS_FREEBSD) ||      \
     defined(OS_NETBSD) || defined(OS_OPENBSD) || defined(OS_DRAGONFLYBSD) || \
-    defined(OS_ANDROID) || defined(CYGWIN) || defined(OS_AIX)
+    defined(OS_ANDROID) || defined(CYGWIN) || defined(OS_AIX) || (defined(__APPLE__) && !defined(OS_MACOSX))
 // Use fread/fwrite/fflush on platforms without _unlocked variants
 #define fread_unlocked fread
 #define fwrite_unlocked fwrite