This report provides an analysis of employer-supported training in Australia. Employer-supported training is the largest share of adult education and training in all Organisation for Economic Co-operation and Development (OECD) countries. It has benefits for individuals, firms, and society. Cross-country studies have shown a positive association between innovation and the proportion of firms in a country providing employer-supported training. Research has also shown that skills development complements the adoption of new technology and innovative human resource management practices to improve the productivity and competitiveness of firms. This study analyses data from the 2011-12 Survey of Adult Skills (PIAAC) for Australia to investigate which individual, labour force and firm characteristics are important in explaining participation in employer-supported training. However, participation is the equilibrium outcome between the supply (employers' willingness to supply training) and the demand (employees' willingness to train) and does not indicate whether the observed inequalities in participation amongst groups of employees is a result of employer behaviour or employee behaviour. Additional information in the PIAAC data on unmet demand for training (training that employees wanted to undertake but could not, mainly because of an unwillingness on the part of the employer to support it) allows researchers to extend the study to explain whether the observed inequalities in participation are related to supply or demand factors. This is important for policy on workforce development in that it helps in the more effective design of targeted programs to address inequalities in participation in training. The results show an unequal distribution of employer-supported training across different groups of employees. For instance, the observed lower participation in training among part-time employees is very much related to employers' reluctance to support their training and very little to do with part-time employees' willingness to train. Appendices are included. [For related reports, see "Workplace Training: Employer and Employee Perspectives" (ED577683) and "Employers' Perspectives on Training: Three Industries. NCVER Research Report" (ED577694).]