William Merrill

William Merrill may refer to:
 * William Emery Merrill (1837–1891), American soldier and military engineer
 * William Henry Merrill (1868–1923), American electrical engineer and founder of Underwriters Laboratories
 * William P. Merrill (1867–1954), American theologian and hymn-writer
 * William Stetson Merrill (1886–1969), American librarian