With the 2015 Paris Agreement, ‘loss and damage’ (L&D) was introduced into the unfccc treaty framework as a new, third substantive area of climate change law. Both before and after its adoption, this new area has been subject to much contention—and this is reflected in a high degree of uncertainty surrounding its interpretation. This article examines the definition of L&D and the types of impact covered by the notion. It also examines the relationship of L&D with mitigation and adaptation, as well as the instruments that are covered by it. Finally, the article considers the controversial issue of who can invoke L&D—and against whom.