This article critically examines the role of informal sport within attempts to increase sport participation. Informal sport is a contested concept that government and non-government agencies are grappling with. In this article, the focus is on participation that is self-organised and not club based. The research reported reflects that at present, policy makers and practitioners have not seriously considered how informal sport may be positioned as a central facet in efforts to respond to participation objectives and associated health and social policy agendas. Drawing on semi-structured interviews with stakeholders responsible for promoting community sport participation in Victoria, Australia, the authors explore some of the tensions and challenges that stakeholders experience in supporting and managing informal sport. The findings indicate that current practices limit the potential of informal sport. Drawing on concepts from collaborative governance, the article concludes that changes to both culture and practices within sport development systems are required in order for stakeholders to harness the potential of informal participation.