Thomas Cosyn (died 1515) was a priest and academic in the late fifteenth and early sixteenth centuries. Cosyn was born in Norfolk. He was educated at Corpus Christi College, Cambridge, graduating Bachelor of Divinity in 1469. He became a Fellow of Corpus Christi in 1462; and Proctor in 1470. He served as chaplain to Elizabeth Talbot, Duchess of Norfolk and held livings at Denton, Norfolk, Kelling and Landbeach. He became Master of Corpus in 1487 where he is said to have "built the buttresses in the old court" amongst other constructions and benefactions to the college.