William Lang

William Lang may refer to:
 * William Lang (American football), coach of the Maryland Terrapins football team, 1908–1909
 * William Henry Lang (1874–1960), British botanist
 * William Dickson Lang (1878–1966), keeper of the department of geology at the British Museum, 1928–1938
 * William Lang (British athlete) (c. 1838–?), professional British runner
 * William Lang (architect) (1846–1897), American architect