This paper focuses on civil liability under competition law in EU and US. Civil liability is a sanction that imposes obligation on a violator of competition law to compensate for losses caused by the activity of violator. Although antitrust regulations in US and EU have stated regarding civil liability, there is ambiguity in law, which has caused the courts not to award the injured parties’ compensation properly. This study is important as civil liability must be analyzed in the field of competition with the increase of anti-competitive behaviors, serious damage caused by them and the necessity of compensating this damage for society. According to Article 101 and 102 of TFEU in EU, the principles of civil liability are based on non-negligent, and according to the Clayton Act, the principles are based on negligence. In US, the method of compensation is based on restitution in kind, but in EU, it is based on pecuniary compensation. Doctrinal research methodology has been adopted to conduct this research. The conditions of injured parties for seeking compensation require better steps, whereby recommendations for the European Commission and the Bureau of Competition have been put forth.