This study was conducted to identify the structural relationship between the perception of school vitality, class improvement activities, and teaching efficacy. The analysis was made using SPSS 26.0 and AMOS 22.0 software and was conducted on the basis of the 9th year (2020) of the Gyeonggi Education Longitudinal Study. The study points to the following: 1. The perception of school vitality had a positive effect on teachers’ class improvement activities. Teachers were more actively involved in class improvement activities when they perceived school vitality to be high. 2. Class improvement activities had a positive effect on teachers’ efficacy. The more the teachers actively participated in class improvement efforts, the higher the perception of the teachers’ efficacy. 3. The perception of school vitality had a positive effect on teachers’ efficacy. The stronger the perception of school vitality, the greater the perception of teachers’ efficacy. 4. The perception of school vitality had a positive effect on teachers’ efficacy, as realized through class improvement activities. Teachers who perceived high school vitality participated more actively in class improvement activities, which, in turn, led to an increase in the level of teachers’ perception in their efficacy. The importance of this study is that it empirically established the relationship between school vitality perception, class improvement activities, and teachers’ efficacy and has also suggested implications of this relationship and the necessity of follow-up research.