Peter Thomas Mahon QC (1 November 1923 – 11 August 1986) was a New Zealand High Court judge. He led a Commission of Inquiry into the 1979 crash of Air New Zealand Flight 901 into Mount Erebus. His assessment of the airline's witnesses having engaged in "an orchestrated litany of lies" is one of the most well-known quotes in New Zealand, brought him offline with the establishment and made him a national hero.