Whithorn (Scots pronunciation: [ˈʍɪthorn]; Scottish Gaelic: Taigh Mhàrtainn), is a royal burgh in the historic county of Wigtownshire in Dumfries and Galloway, Scotland, about 10 miles (16 kilometres) south of Wigtown.

There is a tradition that St Ninian built a church of stone and lime nearby in the late 4th century; it was called Candida Casa, 'White/Shining House'.

The late-medieval cathedral Whithorn Priory is ruinous, much of it having disappeared completely apart from the much-altered aisleless nave and vaults at the former eastern end which once held the shrine of St. Ninian, one of medieval Scotland's major pilgrimage destinations.

A late-medieval gateway with the arms of the King of Scots leads into the site of the priory, which contains the 19th-century parish church and a museum of carved stones (Historic Environment Scotland).

The thirteenth-century Saint Ninian's Chapel marked the point where pilgrims came ashore (the roofless remains are looked after by Historic Environment Scotland).