William Horace Mann (28 July 1878 – 24 February 1938) was an English first-class cricketer who played a single first-class match, for Worcestershire against Hampshire in July 1924. Batting near the bottom of the order he made 4 in the first innings and 3 in the second.
Mann was born in Trowbridge, Wiltshire; he died in Canford Cliffs, Dorset at the age of 59.
He was commissioned a second lieutenant in the Royal Wiltshire Yeomanry (Prince of Wales's Own Royal Regiment) on 16 July 1902.