This chapter investigates why accidents are rarely construed as matters of security and considers the case for giving greater recognition to accidental insecurity in international law and politics. Accidents are far removed from the conventional conceptualization of security politics and yet represent a much bigger threat to most people’s lives than those most typical security concerns: war and terrorism. The average citizen of the world is actually far less threatened by military action from another State or a foreign non-State actor than they are in ways rarely labelled as matters of security. The chapter looks at transport accidents, structural accidents, workplace accidents, and personal accidents. Since the 1990s, both academic and ‘real world’ political discourse has increasingly granted security status to non-military issues in ‘widening’ and ‘deepening’ the agenda of international political priorities. However, security ‘wideners’ and even many human security advocates, while acknowledging that diseases, crime, environmental change, and natural disasters can sometimes be matters of security, are often still reluctant to grant this status to accidents. This reluctance seems to boil down to two objections: (i) there are no military or power politics dimensions inherent in accidents; (ii) accidents are not deliberate attacks on countries or people.