Species that spread uncontrollably in areas beyond their natural ranges are termed invasive alien species. These species are an increasingly widespread problem, adversely affecting all kinds of ecosystems in the world today. Their impacts range from community-level changes in species composition, to changes in soil nutrient characteristics, alterations in disturbance regimes, and negative impacts on ecosystem services such as disruption of the hydrological balance. Prevention and timely control of invasion by alien species is therefore an imperative for conservation of native ecosystems and biodiversity. Repeated observations and monitoring are a means to understanding their behaviour better in order to facilitate action for management. While regular field surveys are a useful means of monitoring invasion on the ground, the time taken and resources required for large area field surveys are often prohibitive. Remote sensing (hereafter RS) is a valuable tool to detect and monitor invasion in large landscapes. In this thesis I consider RS as a methodology to monitor invasion by first reviewing and summarizing existing literature, and later focusing on a single invasive alien plant species — Lantana camara (henceforth Lantana) — in a highly biodiverse mixed forest ecosystem in the Western Ghats of India.