diff --git a/docs/server_manual/services/wms.rst b/docs/server_manual/services/wms.rst
index a7706ca7c10..9d1b5b89deb 100644
--- a/docs/server_manual/services/wms.rst
+++ b/docs/server_manual/services/wms.rst
@@ -331,6 +331,7 @@ Available values are:
 * ``image/png; mode=1bit``
 * ``image/png; mode=8bit``
 * ``image/png; mode=16bit``
+* ``image/webp``
 * ``application/dxf``: only layers that have read access in the WFS service are
   exported in the DXF format