According to official statistics, there are decreasing numbers of Nenets people—the largest group of indigenous small-numbered people in Russia—who know their native language. Moreover, it is mostly elderly people who know the language. Even though children learn the Nenets language at school, they do not know it properly. This is especially true in the Nenets Autonomous Okrug in northwest Russia. In the eight-year period between the population censuses of 2002 and 2010, the number of Nenets speakers in this area decreased threefold. While many factors have contributed to this decline, this article focuses on the legal issues that have impacted the situation. Particular emphasis is given to the inadequate implementation into national legislation of international commitments that guarantee the right of indigenous children to learn their mother tongue at school and the ineffective realization of legal commitments of national legislation concerning this right. This article examines how sources of law concerning indigenous children’s right to learn their mother tongue are implemented and realized in Russia. The focus is on the Nenets Autonomous Okrug.