The European Member States have a poor track-record of transposing directives into the respective national law. This phenomenon is particularly common in the field of environmental policy. This thesis sets out to investigate the underlying reasons for the transposition deficit for all environmental directives that were introduced after the Lisbon Treaty of 2009. Moreover, this thesis differentiates between factors intrinsic to the directive itself and factors that vary from Member State to Member State. Thereafter, this thesis applies a multilevel linear regression analysis based on a growing body of academic literature on the transposition deficit of EU directives in general. The results show that the time-granted for the transposition and the commission delegated directives have an impact on the transposition time. By extension, this means that, for European environmental policies, the type of policy, the complexity of the directive, administrative capacity, degree of decentralization and degree of Pro-Europeanism have no impact on the transposition time.