Belgian development cooperation is undergoing multiple reforms towards more integrated actions intending to improve the effectiveness of its interventions. In line with international debates and engagements, more coherent approaches are promoted that include all different channels and actors and involve those best fitted to reach the objectives of Belgian foreign policy. In this context, the research group “Governance for Development” was asked by DGD to study two particular aspects: i) the trend towards a comprehensive approach that optimizes “horizontal” cooperation between Development, Diplomatic, Defense and Security and Justice actors (also known as 3D, 3D-LO or 3D - Rule of Law approach); ii) the implementation of an integrated country policy (or ICP) for development that optimizes “vertical” collaborations between all actors of Belgian development cooperation around a country intervention strategy. This paper addresses the issue of governance networks as a conceptual framework to better understand these multiple reforms. It argues that the multiple reforms in Belgian development cooperation are illustrations of a broader evolution towards network modes of governance. The basic idea behind governance networks is that many of the contemporary challenges of our world demand the collaboration of diverse public, private and civil society actors. In other words, governments have no longer the monopoly on public policy and more and more multi-stakeholder partnerships are put in place to deal with societal challenges. This is also the case in the policy domain of development cooperation. The paper will illustrate how the concept of governance networks can help to understand success and failure of such multi-stakeholder partnerships in development policy. More in particular, it will be argued that their added value lays in increasing both effectiveness and legitimacy of development policy. The paper consists of two parts. The first part briefly synthesizes the academic literature on governance networks. It ...