One of the key challenges for achieving health coverage that is truly universal is equity – yet this important aspect is often neglected. Investing in policies and systems that explicitly address the needs of the most marginalized and excluded is essential to the success of universal health coverage (UHC). This Issue Paper highlights experience from Thailand in embedding equity in UHC, and provides lessons to promote policies that ‘leave no one behind’. It is based on a forthcoming publication by the United Nations Development Programme (UNDP): The Journey of Universal Access to Antiretroviral Treatment in Thailand, which examines efforts to pursue universal access to treatment for people living with HIV and features various equity-oriented policies and mechanisms.