This paper provides a study of the interaction between public and private enforcement of Lithuanian antitrust law. The study refers to the Damages Directive. It has been found that private enforcement depends greatly on public enforcement of competition law. Therefore, their compatibility and balance are of great importance to antitrust policy. The Lithuanian NCA prioritises cases where an economic effect on competition does not have to be proven. This creates uncertainty about the outcome of private enforcement cases. Private enforcement in Lithuania is also in need of detailed rules on the identification of harm and causality. The analysis reveals how challenging it can be to estimate and prove harm or a causal link in private enforcement cases. Support from the NCA is therefore exceedingly needed. Moreover, even though the use of the leniency programme helps, it remains insufficient to solve the problem of under-deterrence. However, measures introduced by the Damages Directive do not make the leniency programme safe.