diff --git a/README.md b/README.md
index de024a9..0d0afcd 100644
--- a/README.md
+++ b/README.md
@@ -70,6 +70,7 @@ Example:
 ```
 LEAFLET_TILESERVER_URL=https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png
 LEAFLET_TILESERVER_SUBDOMAINS=abc
+LEAFLET_TILESERVER_ATTRIBUTION="&copy; <a href=\"https://www.openstreetmap.org/copyright\">OpenStreetMap</a> contributors"
 ```
 
 ### (Production only) Create cron job