diff --git a/Userland/Libraries/LibWeb/Loader/ResourceLoader.h b/Userland/Libraries/LibWeb/Loader/ResourceLoader.h
index fad5a00eef..fe59236d14 100644
--- a/Userland/Libraries/LibWeb/Loader/ResourceLoader.h
+++ b/Userland/Libraries/LibWeb/Loader/ResourceLoader.h
@@ -40,6 +40,8 @@ namespace Web {
 #    define OS_STRING "NetBSD"
 #elif defined(AK_OS_DRAGONFLY)
 #    define OS_STRING "DragonFly"
+#elif defined(AK_OS_SOLARIS)
+#    define OS_STRING "SunOS"
 #else
 #    error Unknown OS
 #endif