The article explores the conditions for the emergence and consolidation of dynamics of territorial cooperation in the social and solidarity-based economy (SSE), with the example of the French Territorial Clusters of Economic Cooperation (TCECs). From a theoretical perspective, the article draws from the economy of proximity and from the political sociology of the territorial regimes of the SSE. In that sense, the TCECs can be considered as territorial cooperative innovations which indicate, with varying degrees of success, SSE-oriented development paths for the territory. From an empirical standpoint, the trajectory of the South-Aquitaine TCEC, an intersectoral TCEC located in Tarnos (Landes), is compared with two TCECs from the former Rhônes-Alpes region: the Pôle Sud Archer at Romans (Drôme) and Domb’Innov at Trévoux (Ain). The comparison evidences a shared set of conditions favourable to the anchoring and the development of a territorial process of cooperation and clustering in the SSE: areas undergoing economic restructuring; a territorial memory of former successful cooperations; the key-role of a parent organization, be it associative or public, in the activation and hybridization of the territorial resources; a moving formal perimeter of the TCECs. Nevertheless, these TCECs differ substantially with respect to each other concerning the actors involved in the cooperation (associations, cooperatives, private for-profit companies, public authorities) and their priority activities (geared towards job-seekers, inhabitants, local companies or local authorities), the nature and intensity of cooperation between heterogeneous stakeholders, the articulation with territorial development policies, the impact of the SSE footprint on territorial development. The future of the PTCEs, however, remains uncertain and will depend upon state and local policy-making, the transformations of the territorial socio-economies, changes in the interlocking between the SSE and territorial development paths.