William Fremantle may refer to:
William Fremantle (politician) (1766–1850), British courtier and politician William Fremantle (Dean of Ripon, died 1895) (1807–1895), Anglican priest and Dean of Ripon William Fremantle (Dean of Ripon, died 1916) (1831–1916), Anglican priest and Dean of Ripon
See also William Thomas Freemantle (1849–1931), British author and organist