This study deals with key determinants of participation in the nonformal education (NFE) of adults in the Czech Republic (CZE). Our results are based on a secondary analysis of two Adult Education Surveys carried out in the CZE in 2011 (n = 10,190) and 2016 (n = 12,272). Determinants of participation are modelled through logistic regression and decision tree algorithm. The results show that the recent trend of participation in NFE has significantly increased to nearly 40% of adults. In this regard, we argue that this increase is an outcome of the higher investments of employers into NFE in the past 5 years, which has led to a higher proportion of low-skilled workers included in job-related training. Nevertheless, this does not mean that inequality in Czech NFE is decreasing, as the main predictors of participation in NFE remain the same: (a) current employment status, (b) active attitude to learning opportunities, and (c) educational attainment.