In 1987 he was elected a fellow of the Royal Society of Canada and was appointed a university professor in 1990.
He was awarded the Warren Owen Prize in 1989 by the Foundation for Legal Research for his book, The Common Law of Restraint of Trade, which was chosen as the best law book in English published in Canada in the past two years.
He has since authored The Limits of Freedom of Contract and co-authored The Regulation of International Trade; Exploring the Domain of Accident Law: Taking the Facts Seriously; and The Making of the Mosaic: A History of Canadian Immigration Policy.
In 1999, Trebilcock received an honorary doctorate in laws from McGill University and was awarded the Canada Council Molson Prize in the Humanities and Social Sciences.
In the same year he was elected an honorary foreign fellow of the American Academy of Arts and Sciences.