diff --git a/repos/base/include/util/string.h b/repos/base/include/util/string.h
index 9ef7298751..86658d2d32 100644
--- a/repos/base/include/util/string.h
+++ b/repos/base/include/util/string.h
@@ -488,6 +488,12 @@ namespace Genode {
 			{
 				return strcmp(string(), other.string()) == 0;
 			}
+
+			template <size_t OTHER_CAPACITY>
+			bool operator != (String<OTHER_CAPACITY> const &other) const
+			{
+				return strcmp(string(), other.string()) != 0;
+			}
 	};
 }