PurposeOrganizations are increasingly joining inter-organizational networks to foster sustainable employability for their employees. The purpose of this study is to identify the factors and mechanisms central to their success as experienced by key stakeholders.Design/methodology/approachAn explorative, qualitative approach was adopted, using four focus groups with network coordinators (N = 18) and HR professionals (N = 14). Fourteen Dutch inter-organizational networks were represented. Respondents were recruited through purposive and snowballing sampling techniques. Thematic analysis was applied using open coding to generate themes.FindingsThe results of this study outline environmental, structural, and inter-personal factors and mechanisms that contribute to the success of inter-organizational networks that aim to foster sustainable employability for their employees. The environmental factors and mechanisms consist of challenges stemming from the labor market. The structural factors and mechanisms include: a network’s flat structure, flat fee, lack of informal rules, the allocation of roles and expectations for stakeholders and shared network activities. Lastly, the inter-personal factors and mechanisms are: communication among stakeholders, establishing reciprocity, interaction and collaboration between stakeholders, the valuation of trust, a convivial culture and shared vision among stakeholders. The dynamics between these factors and mechanisms are compared to other forms of inter-organizational networks. Furthermore, several recommendations for network coordinators and practitioners regarding the development of networks are presented.Originality/valueThis study provides insights into the factors and mechanisms that are regarded by stakeholders as influencing the success of inter-organizational networks in their ability to foster sustainable employability for workers. We have identified a unique model that captures this new way of inter-organizational collaboration and builds on insights from literature on collaborative governance regimes, institutional fields and entrepreneurial ecosystems. Specifically, the model provides a framework that consists of environmental, structural and interpersonal factors and mechanisms for network success. This study increases our understanding of how collaborative efforts can be fostered beyond organizational boundaries and existing Human Resource Management practices.