Auld St Peter's Kirk is a ruined parish church on Wilson Lane, in Thurso, Caithness, Scotland.
Dedicated to Saint Peter, it dates to at least 1125, and at one time was the principal church for the county, administered by the Bishops of Caithness.
Master Walter Innes, who appears in record in 1554, was vicar of Thurso in 1560, and continued to hold the vicarage between 1561 and 1566.
In 1641, Alexander Monro, minister at Durnoch had from King Charles I, a grant of 800 marks Scots or of eight chalders victual in augmentation of his stipend from the rents of the bishopric in the parish of Thurso and elsewhere.
A 1726 record states, "Above a vault looking into the east end of the church is a session house, but by the permission of the kirk session, it is used by the sheriff and magistrates of Thurso for a court house and prison; and above a dungeon likewise allowed them is a steeple and common clock".