Isaac Barrow was an English clergyman and Bishop, first of Sodor and Man, and then later of St. Asaph. He also served as Governor of the Isle of Man. He is sometimes confused with his more famous namesake and nephew, Isaac Barrow, the mathematician and theologian. Barrow was the son of Isaac Barrow of Spiney Abbey, Cambridgeshire. His father was a landowner and a justice of the peace for more than forty years. In July 1629 the young Barrow was admitted to Peterhouse, Cambridge, where he became a fellow in 1635. In 1641 he was appointed rector of Hinton, but was expelled by the Presbyterians in 1643. Afterwards, he served as a chaplain at New College, Oxford, until the surrender of Oxford to the Parliamentary army in 1646. Barrow bided his time during the interregnum, becoming a Doctor of Divinity. Following the Restoration he received back his fellowship and was appointed a Fellow of Eton College in 1660.

In 1663, however, he resigned his fellowship and was consecrated bishop of Sodor and Man. His nephew preached the consecration sermon. The following year he was appointed Governor of the Isle of Man. During his brief time there he became known as a reformer, establishing schools and improving the living conditions of the impoverished clergy. He established the Bishop Barrow Trust in 1668, and is thus regarded as the founder of what would become King William's College. His arms may still be seen as part of the badge of the college. He was well regarded by his contemporaries for having a generous and kind heart, determined to help the suffering and the poor. He often took money from his private funds to assist those in need. The most notable of such occasions was his purchase of two estates of land, where he provided for the support of young people who wished to pursue careers in ministry. The very next year he returned to England. His health was failing. Still, he was translated to the bishopric of St. Asaph. His health rallied for a time, and his energy returned. During this period he carried out major repairs to the cathedral at St. Asaph's, as well as the episcopal palace and the building of an alms-house for eight poor widows. When he died in 1680 he had plans in the works for a free school at St. Asaph.

Barrow never married. He is buried in the churchyard at St. Asaph. His tombstone created a controversy, since it encouraged worshipers at the church to pray for his soul, which is a Catholic practice not observed by the Church of England.