The purpose of this study was to investigate the relationship among collective teacher efficacy, teacher self-efficacy and organizational citizenship behavior among junior high school teachers in Taiwan. A total of 747 teachers responded to the Collective Teacher Beliefs Scale, the Ohio State Teacher Efficacy Scale and the Extra-role Behavior Scale. The hierarchical linear modeling and the analysis of multilevel mediation were used to analyze data. The major findings of the study revealed that teacher self-efficacy could predict teacher organizational citizenship behavior significantly. Collective teacher efficacy could predict teacher organizational citizenship behavior significantly. Teacher self-efficacy could partially mediate the relationship between Collective teacher efficacy and teacher organizational citizenship behavior.