William Willcox Perrin (11 August 1848 – 27 June 1934) was an Anglican bishop in the late 19th and early 20th centuries.

Perrin was born at Westbury-on-Trym, Somersetshire, on 11 August 1848 and educated at both King's College London and Trinity College, Oxford.^[1][2] Ordained in 1870, he began his ministry with a curacy at St Mary's Southampton and was then vicar of St Luke's in the same city before his ordination to the episcopate as the Bishop of British Columbia.^[3] He was consecrated a bishop on 24 March 1893, by Edward White Benson, Archbishop of Canterbury, at Westminster Abbey.^[4] He was later translated to be the Bishop of Willesden. During this period he was also the rector of St Andrew Undershaft^[2] A noted Freemason^[5] (he kept the rectory until his death).^[6] He died on 27 June 1934^[7] and is buried in the churchyard of St John-at-Hampstead Church, London. His sister Edith was a prominent social reformer.^[8]

Perrin unveiled and dedicated the Hampstead War Memorial in May 1922.^[9]

He retired in summer 1929,^[10] resigning his see in time for his successor's consecration on the Feast of St James (25 July).^[11] He became an Assistant Bishop of London until his death^[6] — he apparently retained oversight of Hampstead deanery throughout.^[12]