While prevailing accounts of victim participation often frame victims as holders of primarily private interests, victims in common law jurisdictions have increasingly emerged as active public participants in criminal justice systems.With a comparative focus on England and Wales and the United States, Victims as Agents of State Accountability recharacterizes victims as agents of accountability in state decision-making. Through historical, empirical, and case-based analysis, this book advances a normative framework that positions the victim's role as a civic duty, enhancing transparency, legitimacy, and substantive equality in prosecutorial decisions. Accordingly, mechanisms of state accountability are examined, such as private prosecutions, judicial review, and internal review schemes, illustrating how their potential for accountability differs depending on whether victims are recognised as advancing primarily public or private interests. Case studies demonstrate the limits of conceiving victim interests as private and the possibilities of substantive assessments of prosecutorial decisions when interests are understood as public.Ultimately, the book contributes to debates in criminal law and justice by proposing an accountability role that is reflexive and equality-driven. Its comparative and normative insights provide guidance for common law jurisdictions and beyond, highlighting the importance of recognising victims as legitimate participants in shaping the public interest and holding the state accountable within criminal justice.