Increases the federal Medicaid matching rate to 90% for eligible behavioral health services (mental health and substance use disorder care) when those services are delivered at a school or a school-based health center, beginning the first calendar quarter at least 12 months after enactment (subject to non‑duplication rules). Creates a competitive grant program to fund adding mental health and substance use disorder providers in schools and school-based health centers, with application, reporting, and allowable‑use rules for recipients.