diff --git a/docker/conf/homeserver.yaml b/docker/conf/homeserver.yaml
index 6bc25bb45f..cfe88788f2 100644
--- a/docker/conf/homeserver.yaml
+++ b/docker/conf/homeserver.yaml
@@ -85,7 +85,7 @@ federation_rc_concurrent: 3
 
 media_store_path: "/data/media"
 uploads_path: "/data/uploads"
-max_upload_size: "10M"
+max_upload_size: "{{ SYNAPSE_MAX_UPLOAD_SIZE or "10M" }}"
 max_image_pixels: "32M"
 dynamic_thumbnails: false