The past two decades have seen a wealth of papers on policy diffusion and policy transfer. In the first half, this paper reviews some of the trends in the literature by looking backwards to the political science diffusion literature, and forwards to the expanding multi-disciplinary social science literatures on policy ‘learning’, ‘mobilities’ and ‘translation’ which qualify many of the rationalist assumptions of the early diffusion/transfer literatures. These studies stress the complexity of context that modifies exports of policy and the need for interpretation or experimentalism in the assemblage of policy. The second half of the paper focuses on role of international organisations and non-state actors in transnational transfer in the spread of norms, standard setting and development of professional communities or networks that promote harmonisation and policy coordination. The ‘soft’ transfer of ideas and information via networks whether they be personal, professional or electronic is rapid and frequent. It is rather more infrequent to see such ideas structure governance and become institutionalised. Knowledge transfer is more extensive than policy transfer.