diff --git a/opal/util/crc.h b/opal/util/crc.h
index 2b77dc6445..82b610ee96 100644
--- a/opal/util/crc.h
+++ b/opal/util/crc.h
@@ -19,6 +19,8 @@
 #ifndef _OPAL_CRC_H_
 #define _OPAL_CRC_H_
 
+#include <stddef.h>
+
 #if defined(c_plusplus) || defined(__cplusplus)
 extern "C" {
 #endif