diff --git a/src/textual/widget.py b/src/textual/widget.py
index 21214c0e46..3fabdc52bc 100644
--- a/src/textual/widget.py
+++ b/src/textual/widget.py
@@ -409,6 +409,7 @@ def __init__(
             id: The ID of the widget in the DOM.
             classes: The CSS classes for the widget.
             disabled: Whether the widget is disabled or not.
+            markup: True if markup should be parsed and rendered.
         """
         self._render_markup = markup
         _null_size = NULL_SIZE