William V. Mong (June 25, 1875 – December 10, 1940) was an American film actor, screenwriter and director. He appeared in almost 200 films between 1910 and 1939. His directing (1911–1918) and screenwriting (1911–1922) were mostly for short films.
He was born June 25, 1875, in Chambersburg, Pennsylvania, and married Esme Warde. He started out as a vaudeville and stage actor, appearing in plays in Los Angeles, Chicago, and New York City. He made his film debut in the 1910 film A Connecticut Yankee.
Mong fell ill in 1938 and stopped acting. He lingered two years, and then died on December 10, 1940, in Studio City, California. He was interred at Grand View Memorial Park Cemetery in Glendale, California.