Data plays an increasingly important role for online platforms and the majority of digital business models. Along with data becoming central to competition and the conduct of actors in digital markets, there has been an increase in data privacy regulations and enforcement worldwide. The interplay between competition and data privacy has prompted questions about whether data privacy and the collection of consumers’ data constitute an antitrust issue. Should competition considerations be factored into decisions by data protection authorities, and, if so, how can synergies between the two policy areas be enhanced and tensions overcome? This paper explores the links between competition and data privacy, their respective objectives, and how considerations pertaining to one policy area have been, or could be, included into the other. It investigates enforcement interventions and regulatory measures that could foster synergies or lead to potential challenges, and offers insights into models for co-operation between competition and data protection authorities. This is a joint working paper from the OECD Competition and Digital Economy Policy Secretariat.