Principle of legal certainty and (in)direct effect of directives

ENPurpose - The research discloses problematic aspects of the case law of the European Court of Justice (ECJ) denying direct effect of the directives between private parties and real effect of (in)direct effect of the directives in the light of the principle of legal certainty. Design/methodology/approach - Research employs logical, systemic, teleological and comparative analysis methods. Findings - Though ECJ still explicitly refers to the ruling made in Marshall case prohibiting horizontal effect of directives, its practice in reality is quiet controversial, begging for discourse and suggestions capable to assist in assuring the respect to the principle of legal certainty. Research limitations/implications - The focus of this article is not to analyse and disclose classical ECJ cases on (in)direct effect of the directives. Research is limited to analysis of exceptions to the rule that denies direct effect of directives and reveals their compatibility with the principle of legal certainty. Practical implications - Key users of rules formed in the case law of the ECJ are national courts that shall assure application of the principle of legal certainty and abstain from acting contra legem.Such research is important in forecasting evolution of the case law of the ECJ in this area for courts and legal advisors that face with doctrine on effects of the directives in practice. Originality/Value - Doctrines on the effect of the directives are of great interest to legal researchers. However, lately ECJ case law allows making more detailed generalizations, though it also leaves certain open questions on the importance of the principle of the legal certainty in relation to principles of effectiveness and supremacy of European Union law. Superior courts of Lithuania usually refer to these doctrines in pretty theoretical aspects, however it is very rarely applied in practice. [From the publication]