diff --git a/i3-save-tree b/i3-save-tree
index b00e1fe1..1e56a045 100755
--- a/i3-save-tree
+++ b/i3-save-tree
@@ -98,7 +98,7 @@ my %allowed_keys = map { ($_, 1) } qw(
     name
     geometry
     window_properties
-    mark
+    marks
     rect
 );