diff --git a/docs/source/reference/configuration.rst b/docs/source/reference/configuration.rst
index 2bc4a250..f22c97dd 100644
--- a/docs/source/reference/configuration.rst
+++ b/docs/source/reference/configuration.rst
@@ -176,6 +176,7 @@ Web application configuration provides the ability to customize web components.
     WIS2BOX_BASEMAP_URL="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"  # URL of map tile server to use
     WIS2BOX_BASEMAP_ATTRIBUTION="<a href="https://osm.org/copyright">OpenStreetMap</a> contributors"  # attribution of map tile server
     WIS2BOX_UI_CLUSTER=False # default setting of the cluster toggle
+    WIS2BOX_UI_LANG="en" # default language, one of: ar, en, es, fr, ru, zh
 
 Other
 ^^^^^
diff --git a/tests/test.env b/tests/test.env
index 7681569d..ed1ad32f 100644
--- a/tests/test.env
+++ b/tests/test.env
@@ -8,6 +8,7 @@ WIS2BOX_DATADIR=/data/wis2box
 # wis2box public URL
 WIS2BOX_URL=http://localhost
 WIS2BOX_UI_CLUSTER=false
+WIS2BOX_UI_LANG=en
 
 # api
 WIS2BOX_API_TYPE=pygeoapi
diff --git a/wis2box-create-config.py b/wis2box-create-config.py
index 4713d94c..fb6f73fe 100644
--- a/wis2box-create-config.py
+++ b/wis2box-create-config.py
@@ -295,6 +295,7 @@ def create_wis2box_env(config_dir: str) -> None:
         fh.write('# wis2box public URL\n')
         fh.write(f'WIS2BOX_URL={wis2box_url}\n')
         fh.write('WIS2BOX_UI_CLUSTER=false\n')
+        fh.write('WIS2BOX_UI_LANG=en\n')
         fh.write('\n')
         fh.write('# api\n')
         fh.write('WIS2BOX_API_TYPE=pygeoapi\n')