The Digital Markets Act (DMA) (Regulation (EU) 2022/1925 of the European Parliament and of the Council on contestable and fair markets in the digital sector and amending Directives (EU) 2019/1937 and (EU) 2020/1828 (Digital Markets Act) [2022] OJ L265/1.) is aimed to address contestability and fairness in the digital arena. The regulatory instrument encompasses the European Union’s largest digital strategies in passing substantive legislation to ensure the right of every citizen to access a trustworthy digital environment (European Declaration on Digital Rights and Principles for the Digital Decade [2022] COM/2022/28 final.), as established by the European Declaration on Digital Rights and Principles for the Digital Decade. Trust as a standalone notion derived from effective enforcement and regulation has been analysed by the organization and management, sociology, or social capital literature. Economic exchanges have also been positively correlated with the existence of trust. Aside from these all-encompassing notions, trust remains widely understated to measure the effectiveness of regulation. The chapter identifies this gap in the literature and ties it in with the measurement of the DMA’s effective enforcement. To do that, the chapter considers the DMA’s impacts on end user trust in relation to its data-related provisions.