St Peter's Church is the parish church of the town of Barnstaple in North Devon, England.
Its oldest parts probably date from the 13th century. The building was enlarged, probably in 1318 when three altars were dedicated by Walter de Stapledon, Bishop of Exeter. To the nave, chancel and tower were added north and south aisles in the Perpendicular style were added later to transform a cruciform church into one of rectangular shape. These aisles were rebuilt in about 1670, but retain mural monuments of earlier date. The church has a lead-covered broach spire, said by Hoskins to be the best of its kind in England.
The advowson and rectory were long the property of Barnstaple Priory (Priory of St Mary Magdalene), of the Cluniac order. Ancient charters were quoted from by Dugdale (d.1686) in his Monasticon Anglicanum (1718 edition in English) thus:
The two-storied Dodderidgian Library (Latin: Bibliotheca Doddridgiana) with wooden mullioned windows was built in 1667 in the north-east corner of the chancel. The Dodderidge Library was founded in 1664 by the widow of John Dodderidge (1610-1659), of Barnstaple and of Bremridge in the parish of South Molton, MP for Barnstaple in 1646 and 1654, who donated or bequeathed her husband's library to the Corporation of Barnstaple. He was the son and heir of Pentecost Dodderidge (d.1650), thrice MP for Barnstaple, the younger brother and heir of Sir John Dodderidge (1555–1628), Justice of the King's Bench and Member of Parliament for Barnstaple in 1589. The books were removed to the North Devon Athenaeum in 1888 and from there in 1957 on permanent loan to Exeter University Library.