Research has shown that students who have higher school attachment have higher academic achievement and less deviant behaviors than those who have lower school attachment. Thus, educators and sociologists suggest that we should focus on nonacademic outcomes, such as school attachment. This study uses TEPS(Taiwan Education Panel Survey) “Wave-1 and Wave-2 student and parent questionnaire” as the main analytic data. It estimated cross-sectional and longitudinal models of teacher’s support on students’ feelings about school on data from 7th- and 9th-grade students. The result shows that (1) Girls have higher school attachment than boys. Aboriginals have higher school attachment than the Han’s students have in 9th grade. Private schools are more attractive to Taiwanese students. The negative effect of peer victimization continuously influences students from 7th grade to 9th grade. 9th graders are less attached to school than 7th graders. More teachers’ emotional support can enhance students’ school attachment, even though students in higher grades have to face much more academic stress on the Basic Competence Test. (2) After controlling for individual characteristics, peer effect and school effect, both teacher’s positive and negative support influence adolescents’ school attachment from 7th grade to 9th grade. In addition, the finding indicates that teacher’s effect on 9th graders’ school attachment is much more than on 7th graders’. That means teacher’s support has different effect that depends on grades. This study provides an effective strategy to increase students’ school attachment which is to focus on teacher’s powerful influence. There is no doubt that peers and teachers are the significant others for adolescents besides parents. The result implies peers are important to adolescents, but the role of teachers in shaping students’ feelings about school has greater effect. Teachers satisfy students’ psychological needs by emotional support. When students perceive love and acceptance, they like school more, which makes them enjoy learning and happier.