Digital markets create many opportunities for states, economies, and societies. Yet, like other markets, they do not always produce the most efficient and morally desirable outcomes. Besides raising questions of privacy and data protection, digital markets have generated competition concerns about abuse of dominance, market entry, and consumer choice. Legislators and regulators worldwide are seeking regulatory policies to address these issues. Yet, whilst policymakers can – in the process of developing ‘pro-competition regulation’ – rely on growing information on the economic aspects of the problems, they have limited knowledge of the competition-related concerns and preferences of citizens (economic and moral). More generally, whilst the study of citizens’ policy preferences is burgeoning, scholars have largely neglected preferences in digital markets. The proposed PhD project analyses UK citizens’ attitudes towards digital markets, focusing on competition-related aspects. It asks five inter-related research questions: (i) What (if any) concerns citizens have regarding the current functioning of digital markets and ‘big tech’ companies? (e.g., in terms of consumer choice). (ii) What do they want digital markets to look like, and why? (e.g., what market conduct do they want to see, and what (limits to) consumer choice do they prefer?) (iii) What type of regime do they prefer for any regulation of the markets, and why? (e.g., to what extent do they prefer self- and government regulation? What sort of rules do they prefer?) (iv) How do their attitudes toward digital markets vary across parts of the population? (e.g., are there differences between generations, the four UK nations, socio-economic groups, and people with different levels of digital market experience?) (v) Does the clarity of citizens’ attitudes vary on different issues and, if so, what drives this diversity? These questions are addressed by using both a representative, nation-wide survey and focus groups. The survey’s focus is on general patterns in citizens’ attitudes and preferences. The focus groups – to be held in the four nations – explore the motivations behind the broader patterns, including the role of citizens’ experience with digital markets. In this way, the project interrogates the legitimacy of the digital market regulation being developed. Legitimacy refers here to the compatibility of regulation with societal norms and principles. Such ‘output legitimacy’ is important in its own right in democracies, but also enhances the success of policies as it facilitates regulatory enforcement and makes business compliance more likely. Moreover, by helping policymakers take citizens into account, the design of regulation is less likely to be disproportionally influenced by business interests. Finally, by exploring the clarity of citizens’ attitudes, the project contributes to a better understanding of the feasibility and appropriateness of citizen engagement by regulators.