diff --git a/README.md b/README.md
index 519749c..1982c42 100644
--- a/README.md
+++ b/README.md
@@ -262,6 +262,8 @@ instead of the default "Directory listing" title.
 The following options allow users to configure various aspects of the
 directory listing:
 
+* `DirectoryListing` (boolean): if true, enable directory listing; if false,
+  return 51 Not found (default value true)
 * `DirectorySort`: A string specifying how to sort files in
   automatically generated directory listings.  Must be one of "Name",
   "Size" or "Time" (default value "Name").
diff --git a/config.go b/config.go
index 6d0c91f..8c29527 100644
--- a/config.go
+++ b/config.go
@@ -36,6 +36,7 @@ type UserConfig struct {
 	PermRedirects         map[string]string
 	MimeOverrides         map[string]string
 	CertificateZones      map[string][]string
+	DirectoryListing      bool
 	DirectorySort         string
 	DirectorySubdirsFirst bool
 	DirectoryReverse      bool
@@ -70,6 +71,7 @@ func getConfig(filename string) (SysConfig, UserConfig, error) {
 	userConfig.DefaultEncoding = ""
 	userConfig.TempRedirects = make(map[string]string)
 	userConfig.PermRedirects = make(map[string]string)
+	userConfig.DirectoryListing = true
 	userConfig.DirectorySort = "Name"
 	userConfig.DirectorySubdirsFirst = false
 
diff --git a/example.conf b/example.conf
index c37104f..2f72de8 100644
--- a/example.conf
+++ b/example.conf
@@ -14,6 +14,7 @@
 #
 ## Directory listing
 #
+#DirectoryListing = true
 #DirectorySort = "Time"
 #DirectorySubdirsFirst = false
 #DirectoryReverse = true
diff --git a/handler.go b/handler.go
index 0de98d5..dc97188 100644
--- a/handler.go
+++ b/handler.go
@@ -318,7 +318,7 @@ func serveDirectory(URL *url.URL, path string, logEntry *LogEntry, conn net.Conn
 	if err == nil && uint64(index_info.Mode().Perm())&0444 == 0444 {
 		serveFile(index_path, index_info, logEntry, conn, config)
 		// Serve a generated listing
-	} else {
+	} else if config.DirectoryListing {
 		listing, err := generateDirectoryListing(URL, path, config)
 		if err != nil {
 			log.Println("Error generating listing for directory " + path + ": " + err.Error())
@@ -329,6 +329,9 @@ func serveDirectory(URL *url.URL, path string, logEntry *LogEntry, conn net.Conn
 		conn.Write([]byte("20 text/gemini\r\n"))
 		logEntry.Status = 20
 		conn.Write([]byte(listing))
+	} else {
+		conn.Write([]byte("51 Not found!\r\n"))
+		logEntry.Status = 51
 	}
 }