William Leach

William Leach may refer to:


 * William Elford Leach (1791–1836), English zoologist and marine biologist
 * William Leach (politician) (1870–1949), British Labour Party politician, minister in the first Labour government
 * William Turnbull Leach (1805–1886), Canadian clergyman and academic
 * William Leach (canoeist) (born 1946), American sprint canoer
 * William Leach (cricketer, born 1851) (1851–1932), English cricketer
 * William Leach (cricketer, born 1883) (1883–1969), English cricketer
 * William Leach (Canadian Army officer) (1942–2015)
 * William Leach (historian), American historian