AbstractWhen an authoritarian state starts democratic transition reforms, the constitution can facilitate such reforms. However, a little-studied role of the constitution during democratic transition is that it can back indigenous peoples’ demands. Constitutional reform during democratic transition enables indigenous peoples to challenge the state's ‘internal colonialism’. The democratic institutions and democratic rights established and guaranteed by the constitution open possibilities for indigenous peoples to push for constitutional reforms that promote ‘internal decolonization’. This means that indigenous peoples are empowered and that their interests are protected. For indigenous peoples, a ‘double transition’ can thus take place: from authoritarianism to democracy, and from internal colonialism to internal decolonization. A case study of the constitutional reforms in Taiwan confirms that the constitution can guarantee indigenous peoples’ participation in constitutional reform. But in Taiwan, this involvement has not led to meaningful incorporation of indigenous peoples in the constitution, and it has not fully promoted double transition. The case study highlights serious problems for indigenous peoples to realize strong constitutional reforms. This article provides a foundation for additional research on constitutional change and indigenous peoples. This is critical to advance constitutional theory and to ascertain whether and how constitutions can give indigenous peoples a voice.