In all societies, past and present, many persons and groups have been subject to domination. Properly understood, domination is a great evil, the suffering of which ought to be minimized so far as possible. Surprisingly, however, political and social theorists have failed to provide a detailed analysis of the concept of domination in general. This study aims to redress this lacuna. It argues first, that domination should be understood as a condition experienced by persons or groups to the extent that they are dependent on a social relationship in which some other person or group wields arbitrary power over them; this is termed the 'arbitrary power conception' of domination. It argues second, that we should regard it as wrong to perpetrate or permit unnecessary domination and, thus, that as a matter of justice the political and social institutions and practices of any society should be organized so as to minimize avoidable domination; this is termed 'justice as minimizing domination', a conception of social justice that connects with more familiar civic republican accounts of freedom as non-domination. In developing these arguments, this study employs a variety of methodological techniques—including conceptual analysis, formal modelling, social theory, and moral philosophy; existing accounts of dependency, power, social convention, and so on are clarified, expanded, or revised along the way. While of special interest to contemporary civic republicans, this study should appeal to a broad audience with diverse methodological and substantive interests.