Thomas Barclay D.D. (June 1792 – 23 February 1873) was a minister in the Church of Scotland and Principal of the University of Glasgow. Barclay was born in Unst, one of the North Isles of the Shetland Islands in the far north of Scotland. He studied at King's College, Aberdeen, the predecessor institution of the University of Aberdeen, graduating M.A., and relocated to London to work as a journalist. He later returned to Scotland to become a minister in the Church of Scotland.