Neville Graeme Marchant (born 1939) is a retired Western Australian botanist.
Marchant began working for the Western Australian Herbarium at the age of 15, as a laboratory assistant to Government Botanist Charles Gardner.
He taught for a short time, including under Professor Brian Grieve, before taking up a scholarship to study at Cambridge University.
After attaining a PhD in plant taxonomy, he won a position on the staff of the Western Australian Herbarium, which he took up in 1970.
He was involved in the development of FloraBase, and the establishment of regional herbaria.