Despite the proliferation of sharing economy initiatives in agri-food systems, the recent literature has still not unravelled what sharing exactly entails from an organizational standpoint. In light of this knowledge gap, this study aims to understand which resources are shared, and how, in a heterogeneous set of sharing economy initiatives in the context of food and agriculture. Specifically, this study compares the organization of various forms of alternative food networks, which are recognized to be frugal forms of sharing economy initiatives, in terms of leadership, bureaucracy, shared resources and participants’ engagement. Data from a comparative case study across 18 AFNs identify five sharing economy models of AFNs with distinctive shared resources and organizational mechanisms: consumer groups; commercial community gardens; as well as network-based, privately owned and publicly owned self-consumption community gardens. These models also display notable differences in terms of their origins, participants’ goals and constraints which, to some extent, may be associated to the nature of their organization. Findings inform policy-makers, AFNs’ leaders and stakeholders—especially those seeking to support innovative models towards sustainable transitions—on how to tailor institutional norms and develop networks to meet the heterogeneous needs of different typologies of sharing economy initiatives in agri-food systems.