William B. Murphy (January 9, 1908 – July 2, 1970) was an American film editor who, in the course of a twenty-year career, served as president of American Cinema Editors (ACE) from 1952 to 1955 and was distinguished in 1966 with ACE's Eddie Award for his work on the science fiction film, Fantastic Voyage, which also earned him an Academy Award nomination for Best Editing.
Born in Mexia, a small city in Central Texas' Limestone County, William B. Murphy was 41 when his name first appeared in film credits as co-editor (with Richard Cahoon) of the independently produced 1949 B-western, Massacre River, released by United Artists. The following year, hired by 20th Century Fox, he worked on several of the studio's 1950s "A" productions, including three Clifton Webb vehicles, Mr. Belvedere Rings the Bell, Elopement (both 1951) and Mister Scoutmaster (1953), as well as Howard Hawks' Cary Grant-Ginger Rogers 1952 comedy, Monkey Business, and the 1957 Pat Boone-Shirley Jones musical, April Love. He also proved adept at westerns, editing Powder River (1953), Three Young Texans, The Gambler from Natchez (both 1954), Stranger on Horseback (1955), Mohawk (1956) and The Lonely Man (1957).