In Chile, the increasing occurrence of socio-environmental conflicts demonstrates that Regional Development Strategies-Estrategia Regional de Desarrollo (ERD)-as the main development policy of subnational territories (Regions), must consider sustainability as a central objective. The Taxonomy of Sustainability constitutes an assessment method that allows us to determine the correlation between the definitions of these public policies and the strategies for transition to sustainable development. The ERD of the Antofagasta and Aysen regions are the ones presenting the highest Taxonomic Index; this indicates a higher strategic content for the promotion of sustainability. It is also noted that the political will that conditions the principles and values on which the ERD are based is strongly determined by investment projects and socio-environmental conflicts, which represent the tension between environmental protection and the capacity and interests of regional society in the development project.