Born and raised in Auckland, Tessa Duder attended the Diocesan School for Girls. As a teenager, she became a national record holder during 1958–59 in both the butterfly and medley swimming events. Tessa went on to win the silver medal in the 110 yards butterfly at the 1958 British Empire and Commonwealth Games and was named New Zealand Swimmer of the Year in 1959. After leaving school, Tessa worked as a journalist in both New Zealand and Europe. In 1964, she married John Duder and for 7 years Tess became a full-time mother of her four daughters, spending much of that time in Pakistan. Tessa later returned to Auckland where she re-entered the workforce as a pianist.
Tessa began writing fiction in 1977, and three years later her first novel Night Race to Kawau was published. Her most successful works are the Alex quartet of novels, which have won three New Zealand Children's Book of the Year awards and three Esther Glen medals. She has performed in several of her own plays and acted in 11 episodes of the soap Shortland Street. Tessa and was made an OBE in the 1994 New Year Honours for services to literature and young people, and has been awarded the Storylines Margaret Mahy Medal. In 2003, she won the Katherine Mansfield Fellowship to work for a year in Menton, France, and in 2007 she travelled to Antarctica under the Artists to Antarctica programme. She was awarded an Honorary Doctorate by the University of Waikato.
Tessa's newest book, First Map: How James Cook Chartered Aoteroa New Zealand was published last month and tells the story of James Cook's expedition and the difficulties he faced in mapping New Zealand's coastline.