diff --git a/components/select/modbus_controller.rst b/components/select/modbus_controller.rst
index b34cd8c23..c288418b5 100644
--- a/components/select/modbus_controller.rst
+++ b/components/select/modbus_controller.rst
@@ -62,6 +62,9 @@ Configuration variables:
 - **use_write_multiple**: (*Optional*, boolean): By default the modbus command ``Preset Single Registers``
   (function code 6) is used for setting the holding register if only 1 register is set. If your device only supports *Preset Multiple Registers* (function code 16) set this option to ``true``. Defaults
   to ``false``.
+- **optimistic**: (*Optional*, boolean): Whether to operate in optimistic mode - when in this mode,
+  any command sent to the Modbus Select will immediately update the reported state. Defaults
+  to ``false``.
 - All other options from :ref:`Select <config-select>`.