diff --git a/bin/named/win32/ntservice.c b/bin/named/win32/ntservice.c
index f309cde999..eb522b4597 100644
--- a/bin/named/win32/ntservice.c
+++ b/bin/named/win32/ntservice.c
@@ -24,6 +24,7 @@
 #include <isc/commandline.h>
 #include <isc/log.h>
 #include <isc/print.h>
+#include <isc/string.h>
 
 #include <named/globals.h>
 #include <named/ntservice.h>
diff --git a/bin/tests/sock_test.c b/bin/tests/sock_test.c
index 74119d89ed..1533d63e67 100644
--- a/bin/tests/sock_test.c
+++ b/bin/tests/sock_test.c
@@ -25,8 +25,9 @@
 
 #include <isc/mem.h>
 #include <isc/print.h>
-#include <isc/task.h>
 #include <isc/socket.h>
+#include <isc/string.h>
+#include <isc/task.h>
 #include <isc/timer.h>
 #include <isc/util.h>
 
diff --git a/lib/isc/win32/socket.c b/lib/isc/win32/socket.c
index bd35bfc370..32972c5d3f 100644
--- a/lib/isc/win32/socket.c
+++ b/lib/isc/win32/socket.c
@@ -67,6 +67,7 @@
 #include <isc/socket.h>
 #include <isc/stats.h>
 #include <isc/strerror.h>
+#include <isc/string.h>
 #include <isc/syslog.h>
 #include <isc/task.h>
 #include <isc/thread.h>