This study aims to analyze the effect of individual school district cadets' motivation to support school districts (intrinsic and extrinsic motivation) on self-efficacy. Furthermore, this study examines the impact of school district cadets' self-efficacy on their organizational citizenship behaviour, as well as the role of self-efficacy as a mediator in the relationship between their motivation to apply and their organizational citizenship behaviour. We conducted a survey of candidates for military school districts in the Republic of Korea. We carried out factor analysis, descriptive statistical analysis, regression analysis, and mediated regression analysis to validate the study's hypotheses. The main statistical analysis results of this study are presented below: First, the external factor, which was one of the motivations for applying to school district cadets, had a positive (+) effect on individual-oriented organizational citizenship behavior, while the intrinsic factor also had a positive (+) effect on this behavior. Second, the study revealed that a positive (+) relationship between external support motivation and individual-oriented organizational citizenship behaviour partially mediated confidence in self-efficacy.