Following the decentralisation of EU competition law enforcement introduced by Regulation 1/2003, the national competition authorities (NCAs) of the EU Member States have become the primary enforcers of Articles 101/102 TFEU. At the same time, the enforcement records of the individual NCAs reported by the European Competition Network display substantial disparity in the number of investigations and envisaged decisions. Previous studies indicate that in several EU Member States, the proportion of EU cases in the overall workload of the NCAs remains low. The existence of the actual or potential effect on intra-Community trade produced by an anti-competitive practice serves as a jurisdictional criterion for the NCA to determine the applicability of EU competition rules in a given case. Therefore, the application of the ‘effect on trade’ concept by the NCAs and national courts can explain the disparity in the enforcement of EU competition rules by individual NCAs. The present paper provides a critical review of the enforcement practice of the Lithuanian Competition Council and Lithuanian administrative courts applying EU competition law, with special focus on the ‘effect on trade’ assessment that determines the applicability of EU competition rules. The incentives derived from this study can serve as a point of reference for other EU jurisdictions where the enforcement of EU competition rules by the NCAs displays similar patterns.