This article aims to investigate the challenges to combat depopulation in the rural sphere, from the inter- and transdisciplinary perspectives of the right to environmental sustainability. In this sense, given that the environment must have considered its intrinsic value and the vital cycles of nature must be preserved as much as possible, in order to avoid the socio-environmental problems that exist today in the world, one wonders: what are these problems and how will they be minimized in an interdisciplinary and therefore legal partner perspective, in the Brazilian and Spanish space? Thus, the specific objectives are: a) to analyze the conceptual contributions of the environment in Brazil and Spain: an approach from the binomial sustainability and coping with rural depopulation; b) to study sustainability and its implementation as a subjective right of the community in the Brazilian and Spanish rural areas. For this, the monographic procedure and deductive approach methods are used, and the research technique is bibliographic. It is concluded that it is clear the need to think about alternatives to socio- environmental problems, either through public policies or through law in the construction of guidelines, aiming to minimize, or even solve, the problem of rural depopulation and environmental degradation, thus implementing smart rural communities and sustainability as a fundamental right, and, consequently, making the rural environment more productive, both in Brazil and Spain.