diff --git a/AK/Platform.h b/AK/Platform.h
index ee51bcc3f9..15b3165cf4 100644
--- a/AK/Platform.h
+++ b/AK/Platform.h
@@ -87,9 +87,17 @@
 #endif
 
 #ifndef __serenity__
+// On macOS (at least Mojave), Apple's version of this header is not wrapped
+// in extern "C".
+#    ifdef AK_OS_MACOS
+extern "C" {
+#    endif
 #    include <unistd.h>
 #    undef PAGE_SIZE
 #    define PAGE_SIZE sysconf(_SC_PAGESIZE)
+#    ifdef AK_OS_MACOS
+};
+#    endif
 #endif
 
 #ifdef __cplusplus