This report is the result of an explorative study, carried out at a time when interest in apprenticeship for adults was on the rise and research and evidence on the topic was scarce and fragmented. It has explored the topic from a conceptual and theoretical point of view, reviewing relevant existing research. It has also considered a practical perspective, exploring policies EU countries and four non-EU countries have in place in relation to apprenticeship for adults. It is the first report that addresses the topic from an EU-wide perspective. Largely based on data collected in 2017-18, the report includes findings from a literature review and field work. It confirms that adults increasingly participate in apprenticeship training, often due to policy interventions and measures that have removed barriers to such participation and provided incentives. The study also confirms that EU countries are fundamentally divided into two main apprenticeship function groups, with two different approaches in aiding participation of adults in apprenticeship.