This article analyzes boundary theory
and
teacher engagement in a pair of suburban U.S. high schools. Cherry Glen, situated
in
a thriving white-collar community, has many college-bound students. Pinehill, situated in a declining blue-collar community, has few such students. A sample of 16 teachers, 8 from each school, was selected for intensive observation and interviewing, along with supplemental data gathering. The study found that boundary relations, evidenced by intergroup relationships, are associated with variation in teachers `sense of engagement, that is, their involvement in and commitment to teaching, to students, and to the school. The more highly bounded high school (Cherry Glen) appears to encourage substantial and relatively uniform teacher engagement. The less bounded school appears to encourage considerable diversity in the level and the direction of teacher engagement. Implications of these findings for secondary education and improvement in school quality are discussed.