This paper aims to examine the legitimacy of Ryukyuans/Okinawans’1 right to self-determination (RSD) under international human rights law. To this end, it first details the evolution of the RSD from the traditional right to independence for colonial peoples, to the continuing right to self-governance for wider groups of peoples, which is followed by an analysis of holders of the RSD. The paper then turns to Ryukyu/Okinawa to discuss the RSD of its peoples. Three historical events, the Disposition of Ryukyu, the Treaty of San Francisco, and the reversion of Okinawa to Japan, are analysed from a legal perspective, followed by an examination of the peoplehood of Ryukyuans/Okinawans. These lead to the conclusion that the Ryukyuans/Okinawans may legitimately claim that they possess the “unexercised” RSD as a quasi-non-self-governing people, and that they are entitled to claim the RSD as a “people” under the International Covenant on Civil and Political Rights, International Covenant on Economic, Social, and Cultural Rights, and other United Nations declarations.