Thomas Buchan (c.1641–1724) was a Scottish professional soldier from a Catholic family in Aberdeenshire who served in the armies of France, the Netherlands and Scotland. He remained loyal to James II after the 1688 Glorious Revolution and participated in the War in Ireland before taking command of Jacobite forces in Scotland in February 1690. After the Highland chiefs submitted to William III in early 1692, he was given safe passage to France and later allowed to return home in 1703. He maintained links with the Stuart exiles and played a small role in the 1715 Rising but escaped punishment and died at Fyvie in 1724.