In the European Union and thus in Italy, there are two main instruments to guarantee effective competition on the markets, and these have converged over time. On the one hand, there is antitrust law, which has been applied so extensively as to become a sort of ‘regulatory antitrust’. On the other hand, there is sector-specific regulation, whose mode and timing of intervention has been aligned to antitrust law approaches to become a sort of ‘pre-emptive competition law’. Debates abound regarding the relationship between competition law and sector-specific regulation as alternative and/or overlapping mechanisms by which to address market failure. The trends indicate that competition law and sector-specific regulation are considered as complements, with companies subject to both regulatory and antitrust scrutiny. In this regard, it must be questioned whether the cumulative approach may, at least in some circumstances, lead to disproportionate results. Indeed, over time, this complementarity has become a critical issue, multiplying jurisdictional conflicts as well as creating a risk of regulatory inconsistency. It is precisely the desire to minimize these concerns that prompted the Plenary Session of the Italian Council of State to displace rules on unfair commercial practices by the application of the principle of lex specialis in the field of consumer protection. Although it is clear that lex specialis does not apply tout court to competition law, this evolution is interesting because it questions the (remaining) differences between the two instruments and their optimal coordination. This chapter seeks to devise solutions for the optimal allocation of jurisdiction between the two types of authorities, which should guarantee a high level of legal certainty and consistent administrative action and ensure compliance with the ne bis in idem (double jeopardy) principle, while not overlooking the fundamental principle of supremacy that characterizes the competition rules enshrined in the TFEU.