This article examines the extent to which the Canadian constitutional framework determines how indigenous customary adoption should interact with Québec law. In the first part, the author uses the theory of legal pluralism to analyse which indigenous interests are at stake in the process of recognizing customary adoption by the State's law. He also argues that customary adoption rules and practices are constitutionally protected under section 35 of the Constitution Act, 1982 and must therefore be recognized by Québec law without being distorted and subordinated to the dominant legal culture. In the second part, the author shows how the constitutional protection of customary adoption is reinforced by the division of powers between the federal Parliament and the provinces. The regulation of aboriginal rights being at the core of the federal jurisdiction over "Indians", it is beyond the reach of the Parliament of Québec. This does not mean, however, that the province is totally deprived of any power to protect children and parents involved in customary adoptions. Nor is Québec denied the powers that are necessary for the reception and application of indigenous custom and its effects in provincial law. Overall, the constitution strengthens legal pluralism with regard to adoption. It imposes a dialogue between indigenous and civil law cultures and, to some extent, it favours their mutual acculturation.