This article provides an overview and critical analysis of inquiries into historical institutional child abuse and examines their multiple functions and complex effects. The article takes a broadly international view but focuses primarily on Australia, the UK and Ireland, jurisdictions in which there have been major national inquiries. Drawing on sociological and other social science literature, it begins by considering the forms, functions, and purposes of inquiries. An overview of emergent concerns with institutional abuse in the 1980s and 1990s is then provided, followed by an examination of the response of many governments since that time in establishing inquiries. Key findings and recommendations are considered. The final sections of the article explore the evaluation of inquiries, both during their operation and in their aftermath. Policy change and legislative reform are discussed but the focus is on aspects often underplayed or overlooked, including an inquiry's credibility, its role in processes of knowledge production, and the part it plays in producing social and cultural shifts. In the context of growing numbers of inquiries across Western democracies, including the Australian Royal Commission into Institutional Responses to Child Sexual Abuse, it is argued that grasping the complexity of the inquiry mechanism, with its inherent tensions and its multiple effects, is crucial to evaluating inquiry outcomes.