After-school youth development programs support social-emotional functioning which leads to better academic and behavioral outcomes. This article examines three common predictors of social-emotional functioning individually and concurrently to better understand the role of these predictors in the after-school setting. The common predictors are staff/student relationships, sense of belonging, and program engagement. That data came from 144, 3rd through 8th grade, students across 9 different elementary and middle school sites who regularly attended a large youth development program. Regression analyses were run and the results indicated that each variable was an individually significant predictor of social-emotional functioning. Results from multiple regression analyses demonstrated that there was a better model fit when including all three variables in the same model. Interestingly, the results indicated that program engagement was a strong predictor above and beyond staff/student relationships and sense of belonging on self-management and self-efficacy. Sense of belonging and program engagement both predicted social awareness. Implications of these findings for after-school program planning and development are discussed.