The aim of this paper is to gain conceptual understanding of changes in leisure-time sports participation (LTSP) as an issue of institutional change. The study is elaborated in the LTSP research context of Flanders (Belgium) and Denmark. Data originate from the Flemish Household Study on Sports Participation (1969, 1979, 1989, 1999, 2009), Danish National Surveys on Sports Participation (1964, 1975, 1993, 1998, 2007, 2011) and the Flemish Participation Survey on Culture, Youth, Sports and Media (2009). A theoretical framework on institutional change is outlined to frame developments in the organisation of LTSP. Next, empirical evidence on changes in LTSP is presented based on time-trend observations and an in-depth analysis of profiles of participants in different organisational settings. The developments seem to reflect post-modern and post-materialist values that are linked to the theory of institutional change. The final part of the paper links changes in leisure-time sports participation to institutional theory in a conceptual framework of ‘greedy’ and ‘light’ institutions. The dynamic character of the framework suggests that both processes of deinstitutionalisation and reinstitutionalisation occur in the field of LTSP. The interpretation of institutional logics related to processes of change may inspire LTSP research from different perspectives.