The primary objective of this investigation was to examine the way in which two facets of the classroom environment (classroom quality and instructional contexts) and children's risk for school problems combine to predict children's behavioral engagement in third-grade classrooms. As part of the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development, observations were conducted on 955 children in 888 third-grade classrooms. Results revealed that children were more likely to be engaged within small groups and during analysis-inference instruction than in large group activities, individualized work settings, and basic skills instruction. Classroom quality and children's risk status were also uniquely associated with behavioral engagement. Children at risk for school problems particularly benefited from higher classroom quality within more demanding instructional contexts. (Contains 3 tables.)