In legal procedures, sanction is understood as a means to put a law into effect, by which the legal subject is compelled to comply with the law by providing incentives for compliance or penalties for infringement. To be effective, sanction needs to have a deterrent effect on the wrongdoer. Competition law sanction varies in different jurisdictions and may include rules of an administrative, private, and criminal law nature. In Indonesia, the competition authority can impose administrative sanctions. However, the law also provides for criminal sanction for the infringement, for which it requires a court decision. The law itself does not mention private sanctions. In practice, it is debatable whether it would be possible to claim damages from a competition law infringer via court. The study is divided into two parts. First, it focuses on sanctioning in competition law in Indonesia: while sanctions usually require a deterrent effect, two issues need further clarification. Secondly, it addresses the challenges needing to be overcome to establish an ASEAN competition law and ASEAN competition law enforcement body, and the attempts to harmonize competition laws of member countries.