John J. Flynn is an American former labor union leader.
Born in St. Louis, Flynn became an apprentice bricklayer in 1952, and joined the International Union of Bricklayers and Allied Craftworkers. He worked in the craft for 20 years, eventually becoming a superintendent. He was elected as business agent of his local union, and then as business manager. Next, he became director of trade jurisdiction for the international union, and then executive vice-president. In this period, he established the union's organizing program.
In 1995, Flynn was elected as secretary-treasurer of the union, and then in 1999 as president. As leader of the union, he promoted training and education for members, and continued to build the organizing program. He also served as a vice-president of the AFL-CIO. He retired in 2010.