Ossian's Hall is a Georgian structure located at The Hermitage in Dunkeld, Scotland.  The Hermitage and Ossian's Hall of Mirrors was originally an unremarkable view-house in a position overlooking the Black Linn falls of the Braan, a tributary of the River Tay. This folly was built on a rocky outcrop for the 2nd Duke of Atholl in 1757.

The Hermitage was redecorated in 1783 as a shrine to the blind bard, Ossian. Ossian is the narrator and purported author of a cycle of epic poems published by the Scottish poet James Macpherson from 1760. Macpherson claimed to have collected word-of-mouth material in Gaelic, said to be from ancient sources, and that the work was his translation of that material. Ossian is based on Oisín, son of Finn or Fionn mac Cumhaill, anglicized to Finn McCool, a legendary bard who is a character in Irish mythology. Contemporary critics were divided in their view of the work's authenticity, but the consensus since is that Macpherson framed the poems himself; based on old folk tales he had collected.

The redecorated hall was intended to evoke features of 'shock' and 'amazement' in the viewers' minds; the room from where views of the waterfall were taken was lined with mirrors which made the spectator imagine that the water was appearing from all angles. William Wordsworth composed a poem which described the 'World of Wonder' in this room. Another description states that in the 1780s, visitors entering were met by a painting of Ossian serenading a group of maidens. The guide operated a device that withdrew the painting into the wall, providing access to another room - a hall of mirrors - giving the illusion of water pouring all around reflecting the river cascading outside. In 1803 the hall had walks that were intersected, here and there, by a small garden of fine flowers among rocks and stones'. These small-scale gardens have since gone.

Garnett in 1800 visited the site. He describes the 'Hall of Mirrors' as having its sides and ceiling covered with mirrors, in which "the cascade is seen by reflection, sometimes running upwards, contrary to the direction of gravity, and sometimes in a horizontal stream over the head."

In 1869 vandals blew up part of Ossian's Hall and the area was left to decay. In 1943 the 8th Duchess of Atholl donated it and 33 acres (13.3ha) of, by then, coniferous woodland along the banks of the River Braan to the National Trust for Scotland in accordance with the wishes of the late Duke. The National Trust for Scotland has restored the building for the use and enjoyment of the public.