Previous research has indicated that student mental health is linked to their engagement at school. However, there is a lack of empirical studies examining students' school engagement from the more comprehensive dual-factor model, which assesses both psychopathology and subjective well-being [SWB]. The current study examined this relationship via an adolescent sample of 611 students in the U.S. Midwest. Results indicated that students with higher levels of engagement experienced lower levels of internalizing or externalizing difficulties, as well as higher levels of SWB. Additionally, linear regressions revealed that as students reported higher school connectedness and academic efficacy, they also reported higher behavioral, cognitive, and emotional engagement. Internalizing difficulties predicted higher behavioral and cognitive engagement, and personal adjustment predicted lower behavioral and cognitive engagement. Internalizing and externalizing difficulties were not significantly associated with emotional engagement. Overall, results indicate that students' mental health factors are closely tied to their engagement at school. These findings can be used to support targeted interventions on well-being and psychopathology, which may increase school engagement and overall student happiness.