diff --git a/packages/react-timerange-picker/src/TimeRangePicker.tsx b/packages/react-timerange-picker/src/TimeRangePicker.tsx
index 34ffb5d..7871ba1 100644
--- a/packages/react-timerange-picker/src/TimeRangePicker.tsx
+++ b/packages/react-timerange-picker/src/TimeRangePicker.tsx
@@ -587,6 +587,7 @@ const TimeRangePicker: React.FC<TimeRangePickerProps> = function TimeRangePicker
         )}
         {clockIcon !== null && !disableClock && (
           <button
+            aria-expanded={isOpen || false}
             aria-label={clockAriaLabel}
             className={`${baseClassName}__clock-button ${baseClassName}__button`}
             disabled={disabled}