This dissertation is devoted to the ethical issues arising in connection to self-tracking practices and technologies. Today, various digital devices (such as Fitbit or Apple Watch) and smartphone apps (e.g.,MyFitnessPal) allow users to collect, quantify and analyse information about their behaviour and bodily parameters, typically for the purposes of behaviour change and management. Self-tracking is commonly associated with the promise of translating quantified data into greater knowledge about oneself, as well as greater control over one’s habits and body. Over the course of the dissertation, I identify the normative issues surrounding selftracking by means of a systematic literature review and adapt John Dewey’s ethical theory to apply it to the analysis of the issues that have not yet been adequately analysed in the literature, namely, the impact on the individual and habit formation, the impact on interpersonal relations, and just distribution of benefits and burdens produced through self-tracking. With the help of Dewey’s ethical ideals of inclusive, continuing growing, and democracy (understood as a cooperative and participatory way of life, rather than a political system), I argue that self-tracking 1) has a negative impact on users’ identity and autonomy by manipulating them into behaviours that are not necessarily in line with their sense of self; 2) limits the quality and depth of users’ engagement with others; and 3) allows companies to exert control over users and profit from their data without adequate compensation, and benefits users from privileged groups to a much greater degree than those coming from marginalised backgrounds. The analysis is accompanied by a set of recommendations for users, developers and policymakers that would ensure that self-tracking positively contributes to individual and societal flourishing/wellbeing and operates in line with the ideal of social justice.