The main purpose of this study was to examinea a model of self efficacy, collective efficacy, and school effectiveness, and to compare the mediation effects of teacher self efficacy with student self efficacy, and to examine the moderating effects of collective efficacyon the relationships between self efficacy and school effectiveness in senior high school teachers and students. The participants, a stratified sample of 314 teachers and 1756 students in Taichung, were administered the Student Self Efficacy Scale, Student Collective Efficacy Scale, Student Perceived School Effectiveness Scale, Teacher Self Efficacy Scale, Teacher Collective Efficacy Scale, and Teacher Perceived School Effectiveness Scale. Structural Equation Modeling was used for data analysis. The results of this study were as follows: (a) the observed data could be interpreted by the model of senior high school teachers’ self efficacy, collective efficacy, and school effectiveness; (b) teachers’ self efficacy partially mediated the relationship between teachers’ collective efficacy and teachers’ perceived school effectiveness; (c) the observed data could be interpreted by the model of senior high school students’ self efficacy, collective efficacy, and school effectiveness; (d) students’ self efficacy partially mediated the relationship between students’ collective efficacy and students’ perceived school effectiveness; (e) teachers’ collective efficacy moderated the relationships between teachers’ self efficacy and teachers’ perceived school effectiveness; (f) students’ collective efficacy did not moderate the relationships between students’ self efficacy and students’ perceived school effectiveness.Based on the results, suggestions were provided for senior high school teachers, students, and future researchers.