Besides emissions reductions, CDR, and adaptation, the only remaining means to limit climate change impacts is solar geoengineering. While it could greatly reduce climate change, including in ways that the other responses cannot, solar geoengineering also poses serious environmental risks and social challenges. For these reasons, it has been controversial, including with respect to international law. In this chapter, I advocate a forceful case that the global testing or deployment of solar geoengineering could be consistent with international law. I secondarily argue that international law even encourages it. To be clear, the fact that solar geoengineering could be consistent with international law does not mean that it necessarily would be. Like all other activities of significant scale, it could be conducted in ways that would be contrary to international law.