Robot accidents are inevitable. Although rare, they have been happening since assembly line robots were first introduced in the 1960s. But a new generation of social robots is now becoming commonplace. Equipped with sophisticated embedded artificial intelligence (AI), social robots might be deployed as care robots to assist elderly or disabled people to live independently. Smart robot toys offer a compelling interactive play experience for children, and increasingly capable autonomous vehicles (AVs) offer the promise of hands-free personal transport and fully autonomous taxis. Unlike industrial robots, which are deployed in safety cages, social robots are designed to operate in human environments and interact closely with humans; the likelihood of robot accidents is therefore much greater for social robots than industrial robots. This chapter sets out a draft framework for social robot accident investigation, a framework that proposes both the technology and processes that would allow social robot accidents to be investigated with no less rigour than we expect of air or rail accident investigations. The chapter also places accident investigation within the practice of responsible robotics and makes the case that social robotics without accident investigation would be no less irresponsible than aviation without air accident investigation.