Over the past fifty years, a diverse set of thermal infrared (TIR) remote sensing data has been acquired from the orbits of Earth and Mars, which both have ubiquitous volcanic landforms. These data vary in spatial, spectral and temporal resolution and are critical for investigating an ever-expanding set of science applications including the focus of this review paper: volcanic processes. Volcanic studies using TIR data include active monitoring of flows and plumes on Earth and mapping the compositional and thermophysical diversity on Mars. Furthermore, recent advances in high-resolution, low-cost, ground and laboratory TIR instrumentation now help to augment the orbital data through a synergistic approach to data analysis and validation. Field and laboratory studies also serve as terrestrially-focused analogues that provide important insights to interpret the geologic processes that have operated on other planetary surfaces including Mars. This review expands upon our invited talk of the same title at the 2014 Geological Society of America Meeting to include several case studies designed to give the reader an overview of how TIR data can be applied to volcanic processes on Earth and Mars. These case studies highlight prior work by the authors presented at past meetings, but which have not been published elsewhere. The examples were chosen specifically to identify the TIR data similarities between the two planets, and include analyses of volcanic surfaces to (1) derive composition and texture using TIR spectra (Earth and Mars); (2) analyze mantled flows with thermophysical data (Earth and Mars); (3) estimate lava discharge rate using TIR-derived temperature (Earth with application to Mars); and (4) model flow dynamics based on geomorphic measurements (Mars). Because of our focus on the TIR, we do not attempt to document other remote sensing wavelength regions nor even every volcanic study using TIR data. As TIR instruments have improved over time along similar trajectories, the higher spatial and spectral resolutions provide the ability to examine volcanic processes in more quantitative ways, despite the fact that no TIR instrument has ever been designed solely to study volcanic phenomena.Whether these trends continue for both planetswill depend on the design of new TIR technologies, the data they produce, and the science that results from the data.