diff --git a/reference/configuration/swiftmailer.rst b/reference/configuration/swiftmailer.rst
index 5eedc920987..1d85e8064da 100644
--- a/reference/configuration/swiftmailer.rst
+++ b/reference/configuration/swiftmailer.rst
@@ -22,6 +22,7 @@ Configuration
 * `transport`_
 * `username`_
 * `password`_
+* `command`_
 * `host`_
 * `port`_
 * `timeout`_
@@ -77,6 +78,13 @@ password
 
 The password when using ``smtp`` as the transport.
 
+command
+~~~~~~~~
+
+**type**: ``string`` **default**: ``/usr/sbin/sendmail -bs``
+
+Command to be executed by ``sendmail`` transport.
+
 host
 ~~~~