This chapter provides an overview of the impact of energetic electron precipitation from the aurora and the radiation belts on the composition, radiative balance, and dynamics of the Earth’s atmosphere, from the lower thermosphere down to the surface. A review is given of the primary processes related to atmospheric ionization and subsequent collision reactions which lead to chemical composition changes in the mesosphere and lower thermosphere. We further discuss the dynamical coupling of these direct impacts to the stratosphere, via downward transport with the meridional circulation in the winter hemisphere, the so-called ’indirect effect’. The observational evidence and current understanding of possible mechanisms that could lead to an impact of energetic electron precipitation on regional surface climate are critically reviewed. Finally, we discuss open issues and obstacles for advancing our knowledge of the impact of energetic electron precipitation on the middle atmosphere and potential climate links.