Margaret Mahy was born and raised in Whakatane, and began writing children's books in earnest at the age of eighteen. Her big break came in 1968 when an American publisher found the text of A Lion in the Meadow and bought it – along with all the other work she had produced over the years; resulting in eight books being published simultaneously.

Mahy became a full-time writer in 1980. Her novel The Haunting won the Carnegie Medal of the British Library Association, and she became the first writer outside the United Kingdom to win this medal. Her work has been translated into fifteen languages and has won the Carnegie Medal three times (in 1982, 1986 and 1987); the Young Observer Fiction Prize (1986); the Italian Premier Grafico Award (1976) and the Dutch Silver Pencil Award (1977). She has also been awarded the Esther Glen Medal of the New Zealand Library Association six times.

Mahy was appointed a writing fellow in New Zealand, Australia, and in the United States. A Summery Saturday Morning won Best Picture Book at the New Zealand Post Children's Book Awards, and 24 Hours received an Honour Award at the 2001 New Zealand Post Children's Book Awards. Alchemy (2002) was shortlisted for the 2003 LIANZA Esther Glen Medal and won the Best Senior Fiction at the New Zealand Post Children's Book Awards 2003.

In 2005, Mahy was awarded the $60,000 Prime Minister's Award for Literary Achievement – the same year she was honoured as an Arts Foundation Icon Award. In 2006, she won the world's premier prize for children's writing, the Hans Christian Andersen Award. Often called the "Little Nobel", the award is given biennially by the International Board on Books for Young People (IBBY) to honour an author who has made a lasting contribution to international children's literature.

Margaret Mahy died 23 July 2012