In 1988, the generalised HIV/AIDS epidemic in Thailand began and in the same year the first HIV-exposed infant in Thailand was born at King Chulalongkorn Memorial Hospital, Bangkok. From the early to mid-1990s, an epidemic wave of HIV-infected women and infants occurred. Heterosexual HIV transmission, as described in the Asian Epidemic Model, was the major mode of spread in Thailand, causing an increasing number of HIV-infected pregnant women. The early and concerted multi-sectoral response of Thai society reduced the prevalence of HIV infection in pregnant women from 2% in the mid-1990s to 0.6% in 2015 and mother-to-child transmission of HIV (MTCT) from an estimated 20-40% to 1.9%. Thus, Thailand became the first Asian country to achieve the World Health Organization's (WHO) targets for the elimination of MTCT. In this narrative review, the key historic evolutions of the science and policy of prevention of mother-to-child transmission of HIV (PMTCT) in Thailand that addressed the four prongs of the recommended WHO PMTCT strategy are described, and the lessons learned are discussed.