William George Helis Sr. (October 17, 1886 – July 25, 1950) was an impoverished Greek emigrant to the United States who made a fortune in the oil business and who became a major owner/breeder of Thoroughbred racehorses and racetrack owner. In his obituary, the Pittsburg Press called William Helis "one of the amazing figures of the American oilfields."^[1]

A resident and legal domicile of New Orleans, Louisiana,^[2] William Helis died at Johns Hopkins Hospital in Baltimore, Maryland. His remains were brought home to New Orleans where he was interred in the Metairie Cemetery.^[3] His mausoleum was built by American architect and sculptor, Albert Weiblen.^[4]

In 1991, William Helis was posthumously inducted into the Fair Grounds Racing Hall of Fame.^[5]

William George Jr. became managing partner of his father's various oil properties and was also heavily involved in Thoroughbred horse racing.^{[citation needed]}