School nurses are crucial to addressing adolescent mental health, yet evidence concerning their evolving role has not been synthesized to understand interventions across levels of practice (i.e., individual, community, systems). We conducted an integrative review of school nurse roles in mental health in the U.S. related to depressive symptoms, anxiety, and stress. Only 18 articles were identified, published from 1970 to 2019, and primarily described school nurses practicing interventions at the individual level, yet it was unclear whether they were always evidence-based. Although mental health concerns have increased over the years, the dearth of rigorous studies made it difficult to determine the impact of school nurse interventions on student mental health outcomes and school nurses continue to feel unprepared and under supported in this area. More research is needed to establish best practices and systems to support school nursing practice in addressing mental health at all levels of practice.