In dualist states, international and domestic legal commitments have traditionally existed on entirely separate planes. Despite the evolution of international legal norms since the end of the Second World War, courts in dualist states have continually opposed using international law to interpret domestic legislation. The author suggests that the traditional dualist view, in which international treaty commitments have no domestic effect until incorporated through the dualist state's domestic legislative process, is weakening.This paper begins with an overview of the monist-dualist distinction in international law and explains dualism's approach to the relationship between domestic and international law. The next section of the paper explores traditional dualist jurisprudence on the role of unincorporated treaties in domestic law and explains why judges have clung to a rigid application of dualism. The weakening of this inflexible approach is then examined, culminating in an analysis of the pivotal recent judgment of the Caribbean Court of Justice in Boyce. This paper concludes that dualism is waning, particularly in cases where domestic law falls short of international human rights standards, as courts demonstrate an increased willingness to use unincorporated treaties as interpretive aids when construing and applying domestic law.