diff --git a/compiler.h b/compiler.h
index 9af5dc6c91..a2d5959e4b 100644
--- a/compiler.h
+++ b/compiler.h
@@ -12,6 +12,12 @@
 #define QEMU_WARN_UNUSED_RESULT
 #endif
 
+#if defined(_WIN32)
+# define QEMU_PACKED __attribute__((gcc_struct, packed))
+#else
+# define QEMU_PACKED __attribute__((packed))
+#endif
+
 #define QEMU_BUILD_BUG_ON(x) \
     typedef char qemu_build_bug_on__##__LINE__[(x)?-1:1];