In the face of dire forecasts of climate change and disappointing emissions abatement, some scientists and others are increasingly suggesting and researching intentional, large-scale interventions in natural systems in order to counteract climate change. These ‘climate engineering’ or ‘geoengineering’ proposals presently appear to hold the potential to significantly reduce the risks from climate change, but they also would pose environmental and social risks and would raise numerous legal questions, particularly at the international level. After introducing climate engineering, this chapter suggests why climate engineering is challenging for international environmental law and its scholars, briefly describes applicable international legal instruments and reviews the existing legal scholarship on the international environmental law of climate engineering, with particular attention to proposals for future international regulation. It closes with suggestions for future research.