小威廉·吉布斯·麦卡杜（William Gibbs McAdoo, Jr.，1863年10月31日 - 1941年2月1日），美国政治家，美国民主党人，曾任美国财政部长（1913年-1918年）和美国参议院议员（1933年-1938年）。

William Gibbs McAdoo, Jr. (October 31, 1863 – February 1, 1941) was an American lawyer and statesman. A political progressive, McAdoo was a leader of the Progressive movement who played a major role in the two presidential administrations of Woodrow Wilson. He was Wilson's campaign manager in 1912; he married Wilson's daughter, and served as his secretary of the Treasury. He was primarily responsible for financing the American side of World War I, providing large loans to the Allies, and running the railroad system inside the United States. He was a leading contender for his party's presidential nomination in 1920 and 1924 and served as Senator from California as a Democrat.