Are states allowed to prohibit the importation of products made by children? Can foreign investors claim compensation when their host state raises the minimum wage? In this book Ruben Zandvliet examines the ways in which international trade and investment law enables and constrains the ability of states to regulate labour. In addition to analysing the interactions between the relevant norms, it explains how linkages between international economic law and labour navigate between two notions: fair competition and fundamental rights. This study is agnostic about which of these objectives ought to shape international law, thus allowing a critical examination of the relevant rules of public international law, as well as legal and economic scholarship.