Robin Tunney was born in Chicago, Illinois to a car salesman father and a bartender mother. Tunney is Irish American; her father immigrated from Ireland and her mother is a first generation Irish-American. Tunney is Roman Catholic, and grew up on the South Side of Chicago. During her freshman year of high school, she attended St. Ignatius College Preparatory School, a co-educational Catholic prep school in Chicago. She then went on to study acting at the Chicago Academy for the Performing Arts.