The unconventional nature of the working environments and tasks of the ROK Army Special Forces (“Special Forces”), as compared to regular army forces, means that Special Forces’ organizational performance is largely influenced by their behavioral patterns and mindset. This study examines the organizational citizenship behavior of Special Forces to enhance their organizational performance. Specifically, this study seeks to investigate the causal path of organizational citizenship behavior and its factors, self-leadership, and trust in the supervisor. Data was collected from Special Forces based in the Seoul metropolitan area during a two-month period, from June to July 2013. A total of 650 questionnaires were distributed, of which 647 were returned. Using 638 questionnaires, excluding those that were unresponsive or filled out incompletely, frequency analysis, reliability and factor analysis, correlation analysis, and path analysis were performed using the SPSS 19.0 and AMOS 19.0 software packages. The results showed that Special Forces’ self-leadership had a significant effect on trust in the supervisor and organizational citizenship behavior, and trust in the supervisor had a partial mediating effect on the relationship between self-leadership and organizational citizenship behavior. Accordingly, this study posits that to enhance Special Forces’ organizational citizenship behavior, it is important to strengthen their self-leadership and trust in the supervisor