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