Alben William Barkley (; November 24, 1877 – April 30, 1956) was an American lawyer and politician from Kentucky who served in both houses of Congress and as the 35th vice president of the United States from 1949 to 1953 under Harry Truman. In 1905, he was elected county attorney for McCracken County, Kentucky. He was chosen County Judge/Executive in 1909 and U.S. representative from Kentucky's First District in 1912. As a representative, he was a liberal Democrat, supporting President Woodrow Wilson's New Freedom domestic agenda and foreign policy.

Endorsing Prohibition and denouncing parimutuel betting, Barkley narrowly lost the Democratic gubernatorial primary in 1923 to fellow representative J. Campbell Cantrill. In 1926, he unseated Republican senator Richard P. Ernst. In the Senate, he supported the New Deal approach to addressing the Great Depression and was elected to succeed Senate Majority Leader Joseph Taylor Robinson upon Robinson's death in 1937. During his 1938 re-election bid, his opponent, A. B. "Happy" Chandler, accused him of using Works Progress Administration employees to campaign for him; Barkley claimed Chandler used state employees in the same way. Neither candidate was charged with any wrongdoing, but in 1939, Congress passed the Hatch Act, making it illegal for federal employees to campaign for political candidates.

When World War II focused President Franklin D. Roosevelt's attention on foreign affairs, Barkley gained influence over the administration's domestic agenda. He resigned as floor leader after Roosevelt ignored his advice and vetoed the Revenue Act of 1943. The veto was overridden, and the Democratic caucus supported and unanimously re-elected Barkley to the position of Majority Leader. Barkley had a good working relationship with Harry S. Truman, who succeeded Roosevelt as president after Roosevelt's death in 1945. With Truman's popularity waning entering the 1948 Democratic National Convention, Barkley gave a keynote address that energized the delegates. Truman selected him as his running mate for the upcoming election, and the Democratic ticket scored an upset victory. Barkley took an active role in the Truman administration, acting as its primary spokesman, especially after the Korean War required the majority of Truman's attention. When Truman announced that he would not seek re-election in 1952, Barkley began organizing a presidential campaign, but labor leaders refused to endorse his candidacy because of his age, and he withdrew from the race. He retired but was coaxed back into public life, defeating incumbent Republican senator John Sherman Cooper in 1954. Barkley died of a heart attack during a speech at the Washington and Lee Mock Convention on April 30, 1956.