Contract is one of the main concepts of transnational regulation. In light of various attempts to harmonize contract law at the transnational level (such as through UNIDROIT), the treaty body itself now forms the backbone of transnational interactions. However, as this chapter explains, contract theory is largely unprepared to understand the constitutive role of contracts in regulating and critiquing transnational social institutions, such as global value chains or digital platforms. In such scenarios, beyond the fact that the contracts are aimed at efficiency between the parties, they manifest a plurality of rationalities and interests and create a space for discourse. Although often fragile, contracts emerge as equivalents of political institutions such that the state legal order no longer provides substantial substantive justice. This chapter examines how the realist and critical traditions in contract theory, in both its American and European forms, are currently being reconfigured to properly reconstruct transnational social conflicts.