Background: Critical resource theory (CReT) provides a framework for the examination and reform of public finance policy. Funding policies for staffing school-based mental health providers have a substantial impact on the structure of service delivery and the ability of youth (and their families) to access much-needed supports in an era of growing mental health needs. Methods: Using CReT, this integrative literature review examines the existing policies and practices of funding for staffing school-based mental health providers. It synthesizes the historical context of United States school finance policy and the current state of school-based mental health systems to identify opportunities for future research, policy, and practice. Findings: The history of residential segregation by race and a complex system of funding sources and allocation methods presents significant barriers for equitable, adequate, and sustainable funding of school mental health staff. However, applying CReT to existing literature revealed sources of funding that can be leveraged and coordinated to provide the necessary staff for school mental health teams. Implications for School Health Policy, Practice, and Equity: An application of CReT with mixed methods and participatory action research designs can support communities in securing the resources to staff adequate mental health systems through informed advocacy.