Regarding the effective implementation of youth sport policies and the promotion of youth sport more generally, the concept of co-determination in sport organizations was introduced in the Norwegian sport political landscape in the early 1990s. It was believed that giving a voice to youth would facilitate the provision of sport for youth. In this article we describe the history of the efforts to establish co-determination processes in the umbrella organization: The Norwegian Olympic Committee and Confederation for Sports (NIF). Drawing on documentary analysis and interviews with key persons, an analysis of co-determination in NIF from 1992 until today reveals two phases with different models for co-determination: first, there was a corporatist committee model (19922004); and second a model based on network organization (2004-2013). With the committee model, youth representatives were elected to a youth committee working as an advisory organ to NIF, and the youth committee's leader was granted a seat on the NIF board. This relationship between the youth committee and the formal board makes the arrangement corporatist. In the network model, youth establish networks to discuss and exert influence on NIF, and youth representatives must be elected similarly to any other candidate. Different organizational models for youth co-determination in sport follow processes based on Rokkan's four concepts of levels of institutional thresholds, differently. This is especially visible in the last two thresholds, representation and executing power, where the corporatist committee model makes more visible influence in NIF than does the network model.