This paper focuses on the procedural instrument of competition expert lay judges to ease damages calculations and private actions for damages for the violation of competition law in general. To this end, the paper analyses various forms of expert lay participation already existent in Europe. It concentrates especially on commercial and intellectual property proceedings but also delves into the few existing examples of competition expert lay judges for private enforcement of competition law. It assesses their transferability for competition damages proceedings and attempts to test EU and national competition as well as procedural law boundaries more generally. The Paper works out common grounds, advantages and disadvantages, as well as best practices. It concludes with first proposals for including competition expert lay judges in private enforcement of competition law.