This chapter provides an overview of the past, present, and future of positive behavior support in the classroom. Early work in classroom management provided an important foundation for the current focus on classroom positive behavioral interventions and supports (PBIS), which prioritizes (a) evidence-based and culturally-responsive practices implemented within a tiered prevention framework (e.g., PBIS); (b) supportive systems that promote effective implementation; and (c) data to monitor for continuous improvement and guide adjustments to promote social, emotional, and behavioral growth for all students. Though current work has moved the field forward in important directions (e.g., promoting equitable access, experiences, and benefit from practices), there are important future directions for. research and practice in classroom PBIS. For example, innovative new research and ongoing enhancements to current practices, systems, and data is needed to fully realize the goal of equitable experiences and benefit for all students and all educators, regardless of demographics (e.g., disability, language, race/ethnicity, gender identity, sexual orientation, SES.