Thailand experienced a generalized human immunodeficiency virus (HIV) epidemic during the 1990s. HIV prevalence among pregnant women was 2.0% and the mother-to-child transmission (MTCT) rate was >20% (1-3). In June 2016, Thailand became the first country in Asia to validate the elimination of MTCT by meeting World Health Organization (WHO) targets. Because Thailand's experience implementing a successful prevention of MTCT program might be instructive for other countries, Thailand's prevention of MTCT interventions, outcomes, factors that contributed to success, and challenges that remain were reviewed. Thailand's national prevention of MTCT program has evolved with prevention science from national implementation of short course zidovudine (AZT) in 2000 to lifelong highly active antiretroviral therapy regardless of CD4 count (WHO option B+) in 2014 (1). By 2015, HIV prevalence among pregnant women had decreased to 0.6% and the MTCT rate to 1.9% (the elimination of MTCT target is <2% for nonbreastfeeding populations) (4). A strong public health infrastructure, committed political leadership, government funding, engagement of multiple partners, and a robust monitoring system allowed Thailand to achieve this important public health milestone.