Sir William Henry Dunn, 1st Baronet (8 October 1856 – 12 June 1926) was a British Conservative Party politician and 589th Lord Mayor of London. Dunn was born in Clitheroe, in Lancashire. He was married to Ellen Pawle in 1885 and they had one son and a daughter. He was elected as Member of Parliament (MP) for Southwark West in the general election of January 1910, taking the seat from the sitting Liberal MP Richard Causton. However he lost the seat back to the Liberals in December 1910, losing to Edward Anthony Strauss.