Mark Alwin Clements (b. 1949) is an Australian botanist and orchidologist. He obtained his doctorate at the Australian National University defending his thesis entitled Reproductive Biology in relation to phylogeny of the Orchidaceae, especially the tribe Diurideae. In 2008 he was a researcher at the Center for Research on Plant Biodiversity at the Australian National Botanic Gardens in Canberra. As of January 2012, it had identified and classified 1,992 new species.