Accidental uses of force between states are common but have received limited scholarly attention. We examine how the possibility of accidents affects interstate relations, focusing on audience reactions, uncertainty, and escalation dynamics. We argue that the possibility of genuine accidents deteriorates information problems in crises because audiences dislike retaliating against claimed accidents, which compounds initiators' incentives to misrepresent. Under uncertainty, this may result in escalation following genuine accidents. Via a survey experiment in the US, we show that substantial audience costs exist for retaliating against claimed accidents, and perceived intent determines public support for the response. Furthermore, third-party information can significantly shift public perceptions of initiator intent. Three case studies involving the US, China, Turkey, and Russia demonstrate the variation in uncertainty, behavior, outcomes, and actors' motivations behind accident or deliberate claims.