Recently, in elementary and junior high schools with an emphasis on regional cooperation, teachers are required to demonstrate teamwork with parents and community residents. However, there is little evidence about what kind of educational effect the teacher-parent-resident teamwork would have on children. The present study aimed to examine the effects of homeroom teachers’ perceptions of teamwork on the intrinsic motivation of children, and the subjective adjustment of children to the classroom, through a classroom social goals structure. A survey was conducted on 2,225 6th grade elementary school students and 3rd year junior high school students and 235 teachers. The multilevel structural equation modeling revealed that the influence of teamwork on intrinsic motivation and subjective adjustment to the classroom was mediated by the social goals structure. The results suggest that the teacher-parent-resident teamwork is an important factor for creating a comfortable class environment.