As students present to school with mental health needs, the role of schools has evolved to include the provision of school-based mental health services delivered across a continuum or multitiered system of supports. Within this framework of services, students can receive intensive mental health services at the Tier 3 level. School-based mental health systems must consider best practices in related fields to ensure schools are well equipped to handle intensive student mental health needs. This exploratory study used a national sample and employed a convergent QUAN+ qual design to explore professional perceptions that were associated with school mental health providers' likelihood of having a proactive plan of care for students in need of mental health supports who are transitioning schools. Quantitative results suggested having sufficient Tier 3 services and sufficient resources (e.g., personnel and time) were associated with school mental health providers using a proactive plan of care. Qualitative results supported this finding and further highlighted potential barriers to school mental health providers' buy in. Additional considerations for facilitating the use of a proactive plan of care in schools and implications for practice are provided. Limitations and future directions are discussed.