diff --git a/.changeset/slick-walls-retire.md b/.changeset/slick-walls-retire.md
new file mode 100644
index 0000000000..87bef48f24
--- /dev/null
+++ b/.changeset/slick-walls-retire.md
@@ -0,0 +1,5 @@
+---
+'@primer/view-components': patch
+---
+
+Always use `aria-selected` for ActionList items with role="option".
diff --git a/app/components/primer/alpha/action_list/item.rb b/app/components/primer/alpha/action_list/item.rb
index 7d47bda908..8166386fb4 100644
--- a/app/components/primer/alpha/action_list/item.rb
+++ b/app/components/primer/alpha/action_list/item.rb
@@ -302,7 +302,8 @@ def before_render
           if @list.allows_selection?
             @content_arguments[:aria] = merge_aria(
               @content_arguments,
-              { aria: @list.aria_selection_variant == :selected ? { selected: active? } : { checked: active? } }
+              # Always use aria-selected for listbox (role="option" requires aria-selected per WAI-ARIA 1.2)
+              { aria: @list.acts_as_listbox? || @list.aria_selection_variant == :selected ? { selected: active? } : { checked: active? } }
             )
           end