A multi-tiered system of supports provides a framework for high-quality implementation of evidence-based mental health practices by educators so that all students have access to a continuum of mental health supports based on need. The purpose of this study was to use survey data to examine 700 educators' perceptions of professional development and preparedness to implement mental health interventions within a multi-tiered system of supports. Descriptive analyses provided information about educator preparedness and access to training, resources, and coaching to support implementation of evidence-based mental health practices across tiers of supports. Further analyses revealed that access to training, resources, and coaching predicted preparedness to provide and assess mental health supports. Educators' perceptions of student access to school and community mental health supports were predicted by access to training, resources, and coaching, and support for evidence-based practices. Perceived preparedness to provide mental health supports predicted whether or not educators reported talking with students about social or emotional concerns. Implications of the findings for professional development practices and policies within multi-tiered system of school-based mental health supports are discussed.