 Remote sensing techniques can provide accurate measurements of radiative energy exchanges between the Sun, Earth, and space. However, more research is needed to understand the magnitude of energy flows within the climate system and at the Earth's surface, which cannot be directly measured by satellites. This review summarizes the basic theories, observational methods, and different surface energy balance algorithms used to estimate evapotranspiration from landscapes and regions with remotely sensed surface temperatures. It also discusses temporal and spatial scaling issues associated with the use of thermal remote sensing for estimating evapotranspiration as well as the results of one study conducted in Taiwan. This article was authored by Yuan Liu and Sanjib Kumar Khar.