While at university, Tizard met Catherine Maclean, while he was president of the Auckland University Students Association. On their second date Tizard told Maclean he was "going into politics. And I'm going to marry you." They married in 1951. The couple moved to Avondale and started a family, with his wife having four children in six years starting at the age of 21 with Anne, followed by Linda, Judith and Nigel. They moved in 1957 to Glendowie in the Tamaki electorate. She then returned to university to complete her degree in zoology, and later began teaching at Auckland university before the couple divorced in 1980. Catherine was later Mayor of Auckland from 1983 to 1990 and Governor-General of New Zealand from 1990 to 1996. He is the father of former Consumer Affairs minister Judith Tizard, who succeeded her father as the Member of Parliament for Panmure in 1990.