The purpose of this study was to examine the relationship among principal's servant leadership, teacher's efficacy, and school organizational commitment. It was also intended to investigate whether principal's servant leadership had any firsthand impact on teacher's school organizational commitment and whether the former exercised any secondhand influence on the latter through teacher's efficacy. This study is ultimately meant to determine the effects of principal's servant leadership. The correlation between principal's servant leadership and teacher's efficacy and organizational commitment was investigated, and the goodness of fit of the research model used in this study was verified as well. And path coefficients were calculated to determine the relationship of the three elements. As a result, it's found that principal's servant leadership exerted an influence on teacher's efficacy and organizational commitment, and that principal's servant leadership affected teacher's organizational commitment through the positive mediating variable of teacher's efficacy. Therefore principals, who are leaders of school organizations, should strive to encourage individual teachers to be convinced of their own ability to meet all the requirements of school organization. They also should urge them to follow what the school organizations pursue and to stay dedicated without leaving their workplace.