富田広士教授退職記念号 To understand the underlying circumstances that facilitate government efforts with robust transparency reform, this study examines the legal strength of Freedom of Information Acts (FOIAs) around the world. This analysis bridges the gap between the institutionalist and civil society focuses of extant research on causes of transparency reform. Given the constellation of major actors and their preferences, this research suggests that the presence of FOIA advocacy groups is an initiating cause for robust reform, while a country's internal institutional arrangement, especially the legislative strength of the chief executive, is a mitigating factor. This study tests two hypotheses — (1) the presence of transparency advocacy is associated with stronger FOIAs ; and (2) the legislative vulnerability of the chief executive is associated with stronger FOIAs, conditional on the presence of transparency advocacy — using cross-national statistical analyses, as well as a comparison of British and German cases. Both support the current study's claim.