Public inquiries, also frequently referred to as commissions of inquiry or Royal Commissions in the Commonwealth, represent one of the most enduring institutions in Western democracies. This chapter focuses on the challenges associated with the study of public inquiries in comparative public policy. The focus is particularly on the few truly comparative studies that exist, as opposed to engaging the broader literature that consists mostly of individual case studies. It tackles the question of what constitutes a public inquiry and why this definition matters in comparative analysis, and briefly discusses their purpose. The chapter summarizes the research contribution of public inquiries into comparative policy analysis by focusing mainly on their characteristics and their impact on policy change. It employs examples from recent research to identify the challenges that the study of public inquiries pose for comparative analysis. The chapter introduces some suggestions on how to stimulate further comparative research in the field.