Sidney Hillman (1887 - 1946) was an American labor leader.
Born in Zagare in Lithuania, he moved to the United States in 1907. A clothing worker, he participated in a successful strike in Chicago in 1910, and, after moving to New York City, became the first president of the Amalgamated Clothing Workers of America in 1914, a post he held until his death. He subsequently helped to found the Congress of Industrial Organizations in 1935, the World Federation of Trade Unions in 1945 and the American Labor Party.
Hillman was more moderate than some of his fellow trade unionists, advocating cooperation between workers and management rather than confrontation. He strongly supported Franklin D. Roosevelt's New Deal and became an influential figure in the Democratic Party.