Nellie Tayloe Ross (born November 29, 1876, St. Joseph, Missouri, U.S.—died December 20, 1977, Washington, D.C.) was an American Democratic politician who, on January 5, 1925, became governor of Wyoming, making her the first woman to serve as governor of a U.S. state; she served until 1927. Ross was also the first woman to direct the U.S. mint (1933–53).

Ross was elected governor of Wyoming in 1924, succeeding her husband, incumbent Democrat William Bradford Ross, who died just prior to the election. A progressive Democrat, Ross supported Prohibition, stricter bank regulations, and increased education funding, among other issues. However, given the state’s Republican-controlled legislature, few of her initiatives passed. After narrowly losing to a Republican candidate for governor in 1926, Ross was appointed vice chairman of the Democratic National Committee.

In 1933 President Franklin D. Roosevelt named Ross director of the U.S. Mint, making her one of the first women to hold a federal post of that importance. During her 20-year term the mint introduced the Roosevelt dime, the Jefferson nickel, and the steel penny, the latter an emergency measure during World War II.

Ross won the distinction of becoming the first woman governor by a small margin; Miriam Ferguson was inaugurated governor of Texas just 15 days later, on January 20, 1925.