The modern slavery discourse has brought attention to the idea of ‘human exploitation’, which underpins a range of practices comprised by this popular umbrella term. Despite its extensive use, the concept of exploitation has never been defined in international law. This article articulates the necessary and sufficient conditions for the notion of exploitation in the context of the human rights prohibition against slavery, servitude, forced or compulsory labour and human trafficking. This is done by examining international legislation, jurisprudence and the philosophical discussions of this concept. Articulating the parameters of exploitation sets firm boundaries of this right while leaving enough room for its further refinement in light of the new and emerging forms of modern slavery. Such analysis is a pioneering effort at elucidating the theoretical foundations of the prohibition of slavery, servitude, forced or compulsory labour and human trafficking.