This article looks at recent developments regarding antitrust class actions in the U.K. and EU. In the U.K., class actions for alleged breaches of competition law are a fairly new phenomenon, having been introduced via the Consumer Rights Act 2015. As with any new regime, the state of class actions is in flux, with the Competition Appeal Tribunal determining key issues on a case-by-case basis. There is no EU-level collective action legislation for antitrust violations, but the new EU Digital Markets Act will provide for collective consumer actions. In addition, several member states have adopted class action regimes, some of which even provide for opt-out regimes.