Inter-particle Coulombic electron capture (ICEC) is an environment-enabled electron capture process by means of which a free electron can be efficiently attached to a system (e.g. ion, atom, molecule, or quantum dot). The excess electron attachment energy is simultaneously transferred to a neighboring system which concomitantly undergoes ionization (or excitation). ICEC has been theoretically predicted in van-der-Waals and in hydrogen-bonded systems as well as in quantum dot arrays. The theoretical approaches employed in these works range from analytical models to electronic structure and (quantum) dynamical calculations. In this article, we provide a com- prehensive review of the main theoretical approaches that have been developed and employed to investigate ICEC and summarize the main conclusions learned from these works. Since knowledge on ICEC is still in its early stage, we conclude this review with our own views and proposals on the future perspectives for the research in ICEC.