diff --git a/tests/unit/plugins/irc/test-irc-ctcp.cpp b/tests/unit/plugins/irc/test-irc-ctcp.cpp
index 76f5340e6..0c1d186f7 100644
--- a/tests/unit/plugins/irc/test-irc-ctcp.cpp
+++ b/tests/unit/plugins/irc/test-irc-ctcp.cpp
@@ -25,6 +25,7 @@
 
 extern "C"
 {
+#include <string.h>
 #include <sys/utsname.h>
 #include "src/core/wee-config-file.h"
 #include "src/core/wee-hook.h"