The Interpersonal–Psychological Theory of Suicide (IPTS) is a framework for understanding suicidality, yet there is little connection of IPTS to school environment, or exploration of this model within various populations. In this article, we conduct a cross-sectional assessment in a high school to understand the relationships between student engagement, IPTS, and suicidal behavior, to provide guidance for counseling professionals to target prevention and intervention efforts to increase effectiveness. A total of 1081 high school students participated in the current study. While perceived burdensomeness was found to moderate the relationship of some aspects of student engagement to suicidal behavior, nuances existed in risk factors to suicidal behavior for various identity groups within the school. Findings have implications for prevention and intervention efforts that would be most effective for students with diverse backgrounds.