John Millen Lasenby (9 March 1931 – 27 September 2019), commonly known as Jack Lasenby, was a New Zealand writer. He wrote over 30 books for children and young adults, many of which were shortlisted for or won prizes. He was also the recipient of numerous awards including the Margaret Mahy Medal and Lecture Award in 2003 and the Prime Minister's Award for Literary Achievement for Fiction in 2014.