Thomas Joseph Hagerty (ca. 1862–1920s?) was an American Roman Catholic priest and trade union activist. Hagerty is remembered as one of the founding members of the Industrial Workers of the World (IWW), as author of the influential Preamble to the Constitution of the IWW, and as the creator of "Hagerty's Wheel", a frequently reproduced illustration depicting the interrelation of the IWW's constituent industrial unions.