The Archdeacon of Lothian was the head of the Archdeaconry of Lothian, a sub-division of the Diocese of St Andrews. The position was one of the most important positions within the medieval Scottish church; because of his area's large population and high number of parish churches, the Archdeacon of Lothian may have exercised more power than many Scottish bishops before the decline in archdiaconal powers after the 13th century.