Gregory John Leach (born 1952) is an Australian botanist.
[1] He has worked particularly on Myrtaceae and Fabaceae and collected extensively in the Northern Territory and Papua New Guinea.
From 1990 to 1991, Leach served as Australian Botanical Liaison Officer at the Royal Botanic Gardens in Kew, London.
[2] He currently works for the Menzies School of Health in Darwin in the Child and Maternal Health Division, working, in particular, on traditional medicinal plants.
Hon (1974) and Ph.D (1982) from La Trobe University.