Thailand's public policy on AIDS is widely cited as one of the few examples of an effective national AIDS prevention program anywhere in the world. The Thai experience shows that a national response that mobilized key government and NGO partners and targeted the highest-risk transmission can be effective in reducing the scope of the epidemic, even when action is delayed. Based on interviews with policymakers, AIDS program managers, technical specialists, donors, and NGOs and on a review of the data, we highlight the lessons from public policy on AIDS in Thailand for other developing countries, review the state of the Thai epidemic and public policy in 2000, and identify three strategic priorities for the next phase of the response.