William Bowers Bourn II (31 May 1857 – 5 July 1936) was an American entrepreneur and socialite. Bourn ran and controlled the Empire Mine and the San Francisco Gas Company, he was an investor in Spring Valley Water Company, and he led a merger to what later became Pacific Gas and Electric Company. Bourn II was the builder of many estates in California, including Filoli, the country estate in San Mateo County, California.