Reducing student problem behavior remains a leading concern for school staff, as disruptive and aggressive behavior interferes with student achievement and the school climate. However, the multi-systemic nature of schools makes it difficult for researchers and practitioners to identify factors influencing to students' behavior. The current study examined student problem behavior through an ecological lens by taking into account individual (e.g., gender, ethnicity, prosocial behavior), classroom (e.g., class size, average classroom behavior), and school-level factors (e.g., location, school climate). Using data from 37 elementary schools, 467 classrooms, and 8,750 students, a series of hierarchical linear models was tested. Multilevel analyses revealed that while individual student characteristics had the largest influence on problem behavior, average prosocial behavior and concentration problems of students within the classroom, as well as teacher perceptions of the school climate significantly related to how students behaved. These findings support the use of classroom-based intervention programs to reduce student problem behavior.