Abraham Alfonse Albert Gallatin (January 29, 1761 - August 12, 1849) was a Swiss-American ethnologist, linguist, politician, diplomat, Congressman, and the longest-serving United States Secretary of the Treasury. He was also a founder of New York University.

Born in Switzerland, Gallatin immigrated to America in the 1780s, ultimately settling in Pennsylvania. He was politically active against the Federalist Party program, and was elected to the United States Senate in 1793, but was removed from office by a 14-12 party-line vote after a protest raised by his opponents suggested he had fewer than the required nine years of citizenship. In 1795 he was elected to the House of Representatives and served in the fourth through sixth Congresses, becoming House Majority Leader . He was an important leader of the new Democratic-Republican Party, and its chief spokesman on financial matters and opposed the entire program of Alexander Hamilton. He also helped found the House Committee on Finance (later the Ways and Means Committee) and often engineered withholding of finances by the House as a method of overriding executive actions to which he objected.