diff --git a/src/textual/widgets/_collapsible.py b/src/textual/widgets/_collapsible.py
index 27215b4159..3331cf9d30 100644
--- a/src/textual/widgets/_collapsible.py
+++ b/src/textual/widgets/_collapsible.py
@@ -58,7 +58,7 @@ def __init__(
         self.collapsed_symbol = collapsed_symbol
         self.expanded_symbol = expanded_symbol
         self.label = label
-        self.collapse = collapsed
+        self.collapsed = collapsed
 
     class Toggle(Message):
         """Request toggle."""