Workplace learning is essential to the continuous improvement and competitiveness of organizations. Antecedent training conditions are crucial for training participation. Despite its recognized importance, few studies have proposed theory-based models for predicting the antecedents of training participation. The principal objective of this study was to test the theory of planned behavior (TPB) for predicting public sector training participation. The second aim was to elucidate the factors that influence, directly or indirectly, employee intentions to participate as well as training participation behavior. The third aim was to test the psychological mediators of past behavior and perceived organizational support on training participation intention of public sector. A sample of 1,108 participants was analyzed by structural equation modeling and hierarchical regression analysis to assess path suitability and significance. The empirical results confirmed the applicability of theory of planned behavior for predicting training participation in the public sector. However, the relationship between past behavior/perceived organizational support and intention to participate was only partially mediated by the direct measures of the TPB. This research adds to the extant training participation literature in several ways. First, it applies the TPB model to develop and examine the behavior and intention of participation in training, and the empirical studies conducted to date have not focused on this field. Second, it identifies several constructs and relationships that are new to this area. Third, this study demonstrates that TPB is a proper way to conceptualize the relevant training constructs. This study can help the public sector managers to encourage employees¡¦ participation in training by improving the time availability and assigning current workload, strengthening social support from family members, co-workers and supervisors. Finally, research limitations and areas for future research are discussed.