This report describes notable variations in how state Medicaid agencies administer and fund Medicaid mental health services. It is based on telephone interviews with all state and District of Columbia Medicaid directors or their designees. Medicaid and mental health agencies are located in the same umbrella agency in 28 states, potentially facilitating collaboration. Mental health agencies provide funding for some Medicaid mental health services in 32 states, and counties provide funding in 22 states. The increasing role of Medicaid in funding state mental health services underscores the importance of interagency collaboration and better alignment of Medicaid and mental health responsibilities.