diff --git a/packages/ui/components/form/timezone-select/TimezoneSelect.tsx b/packages/ui/components/form/timezone-select/TimezoneSelect.tsx
index 5977a7c6bc..fc29857166 100644
--- a/packages/ui/components/form/timezone-select/TimezoneSelect.tsx
+++ b/packages/ui/components/form/timezone-select/TimezoneSelect.tsx
@@ -87,6 +87,7 @@ export function TimezoneSelect({
         menu: (state) =>
           classNames(
             "rounded-md bg-default text-sm leading-4 text-default mt-1 border border-subtle",
+            state.selectProps.menuIsOpen && "shadow-dropdown", // Add box-shadow when menu is open
             timezoneClassNames?.menu && timezoneClassNames.menu(state)
           ),
         groupHeading: () => "leading-none text-xs uppercase text-default pl-2.5 pt-4 pb-2",