Problems related to mental illness are increasingly becoming the focal point of public concern over the safety and performance of schools, yet little is known about the availability and quality of school-based mental health services in the United States. In this article it is estimated that approximately 50% of US middle and high schools have any mental health counseling services available onsite and approximately 11% have mental health counseling, physical examinations, and substance abuse counseling available on-site. There are substantial differences in mental health counseling availability by region, urbanicity, and school size, with rural schools, schools in the Midwest and South regions, and small schools being least likely to offer mental health counseling. Multivariate estimates suggest that disparities between schools in the availability of mental health counseling and related health services may be partly explained by differences in access to Medicaid for financing of health services provided at school.