We start with the development of international law from the tradition of natural law to positive law, and look into how indigenous sovereignty had been extinguished by scholar' discourse, that is, how settler's state had obtained indigenous sovereignty by resorting to the notion of terra nullius. We will then investigate how indigenous sovereignty has been understood, interpreted, and constructed by contemporary scholars, who would challenge the supremacy of state sovereignty and demand reconsideration of indigenous sovereignty and its exercise. Finally, we will examine how the United States, Australia, New Zealand, and Canada have chosen to implement indigenous sovereignty, that is denying indigenous peoples' external sovereignty while allowing for the right to self-determination in the sense of right to self-government.