This research illustrates the role of the Social and Solidarity Economy (SSE) in narrowing territorial, economic and social imbalances while fostering resilience, economic growth and sustainable innovation. Indeed, in a territorial framework characterized by spatial inequalities, the market economy and the public sector might supply an inadequate level of goods and services in socially and/or physically remote places due to an insufficient demand and higher distance costs. Within such scenario, SSE institutions might have a comparative advantage with respect to other institutions in addressing instances and needs of peripheral territories and marginalized actors. Therefore, a potential “institutional gap” shows up, i.e. a relative underdevelopment of SSE institutions, and a lack of clear acknowledgement of the SSE aims and scopes within a broader institutional picture. A major finding is that, when solidarity and social actions can foster the implementation of the SDGs, closer cooperation with other private and public institutions might reinforce mutual institutional recognition, while the observed distortions should be punctually assessed and corrected through appropriate policies. Based on these premises, five scenarios are illustrated and policy recommendations are drawn.