The emergence of Big Data in the digital economy and its corresponding impact on competition law has led to considerable debate in Europe over the last few years. A key concern for competition agencies is the potential harm that might be caused by a company’s ability to acquire datasets that other industry players cannot replicate. It is feared that the control of data may enable these firms to strengthen their market positions and to engage in anticompetitive behaviour, which could deprive consumers of the potential benefits that Big Data offers. Specifically, dominant companies might use Big Data to limit competition or to exploit consumers. In addition, tacit or explicit collusion amongst competitors could be facilitated by greater market transparency and the increasing application of algorithms. In future data-related transactions the potential aggregation of large datasets might also lead to greater scrutiny on the impacts of Big Data and the potential it might have to erect barriers to entry in the specific market and prevent viable competition. As such, regulators and policy makers are contemplating new approaches to ensure that data-related transactions that could significantly impede effective competition do not escape merger control scrutiny. This article considers these potential impacts of Big Data in competition law and outlines the key issues that might need to be addressed.