The purpose of this study was to explore participation in job-related lifelong learning (LLL) among well-educated mature workers and compare it across four Nordic countries. Although this group generally is very active in LLL, the centrality of knowledge work in society, rapid pace of skills-renewal and rising learning demands for all qualifications levels, necessitates a better understanding of the patterns and factors affecting their skill development. The paper builds on theories of learning motivation, human capital and workplace learning. Data from the Survey of Adult Skills (PIAAC) by the OECD were used. In addition to high participation rates, systematic level differences in participation were found across the countries. Results of logit regression analyses revealed clear differences between countries in the models that explained participation, which gave limited support to a single "Nordic model" of LLL. Furthermore, the predictors of participation commonly found among adult populations, low-educated individuals and/or younger adults, appeared less valid for well-educated individuals.