An important theme in recent comparative penology has concerned the apparent convergence of penal policy between 'neo-liberal' Anglophone jurisdictions exemplified by the adoption of a punitive and politicized approach to crime and punishment. At the same time, important divergences from this pattern have been noted in other national contexts, not least in a number of Western European countries. This article returns to these debates in light of the history of the passage of federal and state legislation in the area of sex offender community notification in the United States (Megan's Law) together with campaigns to enact similar legislation in the UK (Sarah's Law). We compare the process of policy change on both sides of the Atlantic and analyse the factors shaping key policy decisions. A central objective is to explore the ways in which broader cross-national influences and distinctive national political institutions and structures work to shape the agendas and actual decisions of key policy actors. The article concludes with some observations about the nature of convergence and divergence in the penal policies of different nations. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.