Exploring why the long existing word “territory” is increasingly used to address current sustainability challenges seems a worthwhile effort. Beyond its polysemy, the territory is considered here as having both spatial and social characteristics, liaising for instance at the local level between community and landscape. At the local level, the territory contributes to the provision or management of public goods and has the capacity to generate changes. This concept provides an analytical and operational framework for addressing public regulation needs through the strengthening of targeted collective action, through the partial resolution of market and state failures and through the connection between collective and public action. The text finally looks at commonalties and specificities between the two concepts of socio-ecosystem and territory.