This chapter seeks to shed light on the role of non-State actors in custom-making processes. It does so by repudiating the dominant understanding of opinio juris and practice within the two-element variant of the doctrine of customary law that has informed practice and scholarship since the 1920s. It shows that dominant approaches to opinio juris and practice are indifferent to the role of non-State actors by virtue of constructions that are highly questionable. Section 1 sketches the dominant understanding of two elements of customary international law. Section 2 discusses the limitations of the dominant understanding of opinio juris by showing the extent to which the anthropomorphic concept of opinio juris fails to perform the functions assigned to it. In section 3, the attention turns to practice which contains a greater variety of approaches. This section particularly emphasizes the role of domestic non-state actors in the creation of international norms that shapes State practice, and increasing role of international organizations to strengthen the grips of the domestic actors in creating international customary norms through the member States. This chapter ends with a few concluding remarks about the general implications of the approach promoted here for the doctrine of customary law as a whole.