Margaret Grace Thorsborne AO (3 June 1927 – 16 October 2018) was an Australian naturalist, conservationist and environmental activist. She was notable for her efforts, with her husband , in initiating the long-term monitoring and protection of the Torresian imperial-pigeon on the Brook Islands, north east of Hinchinbrook Island, Far North Queensland. Toward the end of her life, she was involved in the struggle to protect Queensland’s Wet Tropics World Heritage Area and animals such as the southern cassowary, mahogany glider and dugong.