William Henry Vanderbilt III, born November 24, 1901 - died April 14, 1981, was an American statesman and a member of the prominent United States Vanderbilt family.

Born in New York City, he was the son of Alfred Gwynne Vanderbilt and Ellen French. His parents divorced in 1908 and through his fathers second marriage he had two half-brothers, Alfred G. Vanderbilt II and George Washington Vanderbilt III. In 1915, his father perished in the sinking of the RMS Lusitania. In 1934, his cousin on his mother's side, Ellen Tuck French, married John Jacob Astor VI, bringing together two of America's most famous families.

Educated at St. George's School in Middletown, Rhode Island and the Evans School in Mesa, Arizona, he attended Princeton University but dropped out during his first year. At age of maturity, Vanderbilt inherited a $5 million trust fund plus the 450 acre (1.8 km²) "Oakland Farm" in Portsmouth, Rhode Island, one of his father's estates that included a number of thoroughbred horses. He made the farm his permanent home, and in 1925 started a bus company, carrying passengers between Newport and Providence. Within a few years he expanded the business to serve points throughout New England and New York. A member of the United States Republican Party, in 1928 he was a delegate to the Republican National Convention from Rhode Island and that year was elected to the State Senate.

William Henry Vanderbilt III served in the Senate for six years then took time off to be with his sick wife, Anne Gordon Colby. On her recovery, he re-entered political life and successfully ran for Governor of Rhode Island, serving between 1939 and 1941. However, his refusal to dole out patronage to fellow Republicans weakened his power base and a scandal over wire-tapping by a private detective firm he had hired to investigate election fraud, cost him re-election. Shortly thereafter, when the United States entered World War II, Vanderbilt joined the United States Navy.

He eventually left Rhode Island and moved to a farm in South Williamstown, Massachusetts where he lived quietly until his passing in 1981 at the age of 79.