The aim of this study was to assess how training motivation in terms of the expectation of gaining valued outcomes (i.e., motivation through expectation) and motivation to learn explains participation in training and development. Direct, mediator, and moderated explanations were tested. Survey data were gathered at Time 1 and a year later at Time 2, providing a longitudinal sample of 1705 Australians. Multiple regression analyses showed that, the higher the training motivation (both types), the more employees participated in training and development in the next 12 months, as they also did from higher supervisor support. Training motivation did not mediate the effects of the work environment on participation but moderated the prediction by employer support. Employer support predicted participation in training and development in the next 12 months more for employees with higher than lower training motivation. Motivation to learn and motivation through expectation, chiefly instrumentality, similarly explained participation in training and development.