he main aim of this paper is to cast light on the case law on direct effect of directives, which has remained elusive to both scholars and practitioners. To this end, we first revisit the relevant case law on inverse vertical, horizontal. and triangular disputes to show that the fundamental distinction drawn by the case law is that between ‘direct obligations’ and ‘mere adverse repercussions’. Subsequently, we propose a doctrinal approach to distinguish between ‘direct obligations’ and ‘mere adverse repercussions’ which centres on the impact of invoking a Euorpean Union (EU) directive on the norms governing the dispute. This ‘normative impact theory’ explains all existing case law on the direct effect of directives, and thus aids a better understanding of the concept of imposing obligations on individuals. We compare this theory with other doctrinal theories that have purported to explain the case law, including the well-known distinction between invocabilité de substitution and invocabilité d’exclusion, concluding that the normative impact theory has descriptive and normative advantages over existing approaches. Lastly, we show how the functioning of the preliminary reference procedure has affected the development of the case law on direct effect. We demonstrate that the European Court of Justice (ECJ) applies a presumption that consistent interpretation is capable of remedying incompatibilities between national and EU law. Secondly, we show how the formulation of the preliminary reference can substantially affect, and even confuse, the answer of the ECJ as regards matters of direct effect.