The transnationalization of public policy has in part been driven by knowledge networks, but the role and functioning of such networks have also been transformed in the process. This chapter discusses some key contributions in the study of knowledge networks in transnational policy from both public administration and from International Relations, and highlights areas where there is scope for cross-fertilization. Three issues merit attention. First, the ways in which normative commitments are linked to or articulated with knowledge production and how this shapes the role and functioning of knowledge networks. Second, how the emergence of evidence-based policy and the reliance on ‘objective’ measures as a basis for public policy transforms the status of expertise and may undermine the idea of the expert as providing judgements. Third, how transnationalization is also a process of differentiation, which renders our analytical vocabulary less useful, since a key feature of differentiation is the blurring and re-drawing of boundaries between actors and activities.