diff --git a/grep.c b/grep.c
index 14a9e66..bab1f18 100644
--- a/grep.c
+++ b/grep.c
@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
 
 #include "queue.h"
 #include "util.h"
diff --git a/kill.c b/kill.c
index 5c5f5dd..05255db 100644
--- a/kill.c
+++ b/kill.c
@@ -7,6 +7,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
 
 #include "util.h"
 
diff --git a/logger.c b/logger.c
index 5e1c0a4..36d3a3a 100644
--- a/logger.c
+++ b/logger.c
@@ -2,6 +2,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
 #define SYSLOG_NAMES
 #include <syslog.h>
 #include <unistd.h>