diff --git a/include/nuttx/syslog/syslog.h b/include/nuttx/syslog/syslog.h
index 073d11646cf..d6010448adb 100644
--- a/include/nuttx/syslog/syslog.h
+++ b/include/nuttx/syslog/syslog.h
@@ -42,6 +42,7 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
+#include <stdarg.h>
 
 /****************************************************************************
  * Pre-processor Definitions