diff --git a/middleware/filesystem/filesystem.go b/middleware/filesystem/filesystem.go
index f4f3f435..87c23c96 100644
--- a/middleware/filesystem/filesystem.go
+++ b/middleware/filesystem/filesystem.go
@@ -62,6 +62,9 @@ func New(config Config) fiber.Handler {
 	if !strings.HasPrefix(cfg.Index, "/") {
 		cfg.Index = "/" + cfg.Index
 	}
+	if cfg.NotFoundFile != "" && !strings.HasPrefix(cfg.NotFoundFile, "/")  {
+		cfg.NotFoundFile = "/" + cfg.NotFoundFile
+	}
 	if cfg.Root == nil {
 		log.Fatal("filesystem: Root cannot be nil")
 	}