Robert Ussher (4 April 1592 – 18 July 1642) was an Irish Protestant bishop who served as the 6th Provost of Trinity College Dublin 1629 to 1634.
The youngest son of Henry Ussher, Archbishop of Armagh and his first wife Margaret Eliot, daughter of Thomas Elliott of Balreask, he was educated at Trinity College Dublin, being made a fellow in 1611, and graduating B.A.
He owed his appointment to a temperate letter in his favour by his cousin, James Ussher, to whom an appeal had been made.
He was an able preacher, promoted the study of the Irish language, and defended the college's charter rights; but was considered too dovish by the formidable Thomas Wentworth, 1st Earl of Strafford.
He died at Panta Birsley, near Ellesmere, Shropshire, on 7 September 1642, and was buried at Dudleston (Doddleston) Chapel, near Oswestry.