 O'Regan studied at the University of Cape Town from 1975 to 1980, earning a BA and LLB.She was taught briefly by Arthur Chaskalson, who had recently founded the Legal Resources Centre, and ran UCT's legal aid project, working with Mahomed Navsa of the University of the Western Cape.After earning an LLM from the University of Sydney, she returned to South Africa and began her articles of clerkship at Bowman Gilfillan.