The Ballroom dates from 1876, when the 7th Duke of Atholl employed architect David Bryce to add a new front entrance and ballroom to the castle. The ballroom incorporates a hammer-beam ceiling and butternut wood panelling on the walls.

The room was initially built to host the annual Atholl Highlanders' Ball, with the inaugural taking place on the 5th of September 1877. It was here that the first 'Eightsome Reel', devised by the 7th Duke and his cousin the 7th Earl of Dunmore, was danced.

The Ballroom continues to host Highland balls, weddings and events.