diff --git a/lib/mix/tasks/mobilizon/instance.ex b/lib/mix/tasks/mobilizon/instance.ex
index a5bf2d648..7cb4da48d 100644
--- a/lib/mix/tasks/mobilizon/instance.ex
+++ b/lib/mix/tasks/mobilizon/instance.ex
@@ -24,6 +24,7 @@ defmodule Mix.Tasks.Mobilizon.Instance do
   - `--dbname DBNAME` - the name of the database to use
   - `--dbuser DBUSER` - the user (aka role) to use for the database connection
   - `--dbpass DBPASS` - the password to use for the database connection
+  - `--dbport DBPORT` - the database port
   - `--listen-port PORT` - the port the app should listen to, defaults to 4000
   """