diff --git a/usr.bin/gcore/elfcore.c b/usr.bin/gcore/elfcore.c
index 0881ceb3682..bdfd9bb459d 100644
--- a/usr.bin/gcore/elfcore.c
+++ b/usr.bin/gcore/elfcore.c
@@ -29,6 +29,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/procfs.h>
+#include <sys/queue.h>
 #include <sys/linker_set.h>
 #include <machine/elf.h>
 #include <vm/vm_param.h>