Sir James Leyburn (c. 1490 – 20 August 1548), also Laybourne, Labourn, etc., was a senior representative of one of the powerful families within the Barony of Kendal. He was at different times a Justice of the Peace for Westmorland, Escheator for Cumberland and Westmorland, and Commissioner for the survey of the monasteries of Lancashire. He was caught up in the troubles at Kendal during the Pilgrimage of Grace (1536-1537). As an assistant (and kinsman) to Sir Thomas Wharton, Deputy Warden of the West March, he took an important part in the Battle of Solway Moss (1542). He was one of the two MPs for Westmorland in 1542 and 1545.