The Collegiate Church of St Mary in the Fields (commonly known as Kirk o' Field) was a pre-Reformation collegiate church in Edinburgh, Scotland. Likely founded in the 13th century and secularised at the Reformation, the church's site is now covered by Old College.
The Augustinian monks of Holyrood Abbey held superiority over the church and likely founded it as a centre of education in the 13th century. The church appears to have been raised to collegiate status in the early 16th century. Around this time, erection of the Flodden Wall brought the church just within the bounds of the city and overlooking the Potterow Port, which was also known as the Kirk o' Field Port. After the church was secularised at the Reformation, the town council acquired its land and provostry. The area became the first site of the town's college: later, the University of Edinburgh. The church is also notable for its association with the murder of Henry Stuart, Lord Darnley, husband of Mary, Queen of Scots, which took place in the vicinity in 1567.
