Thomas Gillespie is an American geographer and professor of geography at the University of California, Los Angeles (UCLA). Gillespie's main area of research is in determining the patterns of species richness within a given geography, specifically native Hawaiian flora and tropical dry forests in biodiversity hotspot such as Hawaii, Sundaland, Indo-Burma, New Caledonia and the Caribbean, through remote sensing and GIS. His research has been used to inform global conservation policies and natural resource/tropical ecology management.