The paper presents and addresses the concept of “spontaneous sustainability”, the informal and unplanned sustainable development of communities, as the basis and framework to support the notion, drives, and agendas of “formal sustainability”. It follows the interdependence between the “spontaneous sustainability” of “distinct” communities and their “cultural” characteristics, including history, spatial continuity, values and behaviors, the associated physical settings, and tangible and intangible products, which enabled them to continue, survive, and develop. The research aims at formulating and validating a “framework” for monitoring and enhancing the “spontaneous sustainability” of “distinct” communities to enable, support and link it, to the broader frameworks of “sustainable development”. The proposed “framework” combines “sustainability” dimensions: environmental, economic, and socio-cultural; and the levels of community contexts, and spatial impact. The “framework” is formulated by integrating selected “urban sustainability” approaches, and systems, with later research that developed the key aspects, criteria, and indicators of those systems, together with research addressing “social and cultural sustainability”, and assessment aspects, criteria, and indicators. The “framework” is developed and validated through a limited questionnaire, involving local experts and specialists, academics, and practitioners, to point out limitations and potential, and to suggest the relative importance of its components, key aspects, and criteria. The validation supported the research propositions, the formulation, and development of the proposed “spontaneous sustainability framework” and emphasized its flexibility to include other approaches and agendas, and potential for further development and application in distinct local communities.