This article explores the use of the Multilevel Governance (MLG) concept to understand why EU Member-States, such as Belgium, sometimes fail to transpose EU directives correctly or in time. Firstly, it discusses the nature and the value of the MLG concept. It is argued that a theoretical incorporation of the MLG concept in the Neo-Institutional (NI) paradigm is necessary to gain explanatory power. Secondly, an overview is presented of the Belgian implementation record. In the last part, the combined use of the MLG concept and the NI theory identifies several factors to explain failing implementation. It is argued that governance as well as multilevel institutions can constrain the desired smooth implementation. Examples of such hard and soft institutions include the multi-layeredfederal structure of Belgium, the complex co-ordination and implementation mechanisms, the role of advisory bodies and the Council of State, the relation between administrations and 'cabinets', and cultural features such as knowledge of the EU.