Lester John Castle CMG (13 July 1921 – 26 November 1986) was the Chief Ombudsman of New Zealand from 1984 to 1986. In this role, he was responsible for investigating complaints against central and local government agencies, including Ministers of the Crown. Castle was appointed a Companion of the Order of St Michael and St George in the 1977 Queen's Silver Jubilee and Birthday Honours, and was awarded the Queen Elizabeth II Silver Jubilee Medal the same year.