Our study elucidates relational value creation and appropriation in collaborative networks for sustainability (CNfS) that focus on grand societal challenges and include a multiplicity and diversity of actors. Using a relational view lens, we conducted a longitudinal, multiple case, field study of collaborative networks for sustainability in the circular textile and fashion industry, unpacking the interplay between value creation from relational interdependence, relational-specific assets and material output and the multilevel appropriation of that value. Our findings show that value appropriation is contingent on the perception of relational use value and cascades through individual, organizational and network levels. The ability of actors to capture cascading value on different levels has a direct influence on the sustained continuity of value creation and to achieving the shared societal goals of CNfS. We developed a model of value appropriation in CNfS to illustrate the cascading flow of value at micro (individual), meso (organizational) and macro (network) levels. Our study makes novel contributions to the literatures on strategic alliances, cross-sector partnerships, and open innovation networks.