Recent work in republican political theory has identified various forms of domination in the structures and relations of capitalist societies. A notable absence in much of this work is the concept of exploitation, which is generally treated as a predictable outcome of certain kinds of domination. This paper argues that the concept of exploitation can instead be conceived as a form of structural domination, understood in republican terms, and that adopting this conception has important implications for republican attempts to theorise modern capitalist societies. Building on existing domination accounts of exploitation, we argue that exploitation is a form of structurally constituted domination that enables a systemic illegitimate extraction ofvalue. However, in contrast to competing accounts, domination is understood here in the republican terms of subjection to arbitrary power. We show that conceiving of domination in these terms not only makes the concept easily accessible from within a republican framework, but has advantages over competing accounts. Our argument also demonstrates why using the concept of exploitation will be useful for republican theorists. We show that a polity based on exploitative relations of production is antithetical to key republican commitments. These asymmetric power relationships undermine the economic and political independence of citizens and, crucially, constrain the political and economic ends that a polity will be effectively able to pursue. As such, exploitation should be a central preoccupation of republican political economy.