This article investigates variations in the domestic impact of the European Union's largest financial instrument, the European Social Fund (ESF), in The Netherlands and Spain. We find that, despite the large differences between the two countries examined in terms of ‘goodness of fit’, the ESF had significant effects on both The Netherlands and Spain. These effects, however, occurred through rather different dynamics: intermediate variables such as leverage, learning and aid conditionality determine how the ESF actually ‘hits home’, in addition to the degree of institutional, political and policy (mis)fit. At the same time, we qualify our analysis by exploring the role of countries' past experiences with the ESF, their problem load, the availability of (European Union and domestic) resources and member states' uploading capacities. The ‘goodness of fit’ literature has suggested that these factors may be important, but they have not yet been sufficiently explored for the ESF.