Set against existing explanations for Thailand’s landmark universal coverage policy, this chapter traces the historical rise of a movement of progressive physicians in Thailand (the Rural Doctors’ Movement). After establishing their origins, it explores the critical role they played in institutionalizing universal healthcare over powerful opposition forces. In the absence of the strategic actions of this professional movement, the evidence presented here suggests that there is little reason to believe that Thailand’s universal coverage policy would ever have become a major issue in the 2001 election, much less a policy that would have been implemented and gone on to receive international acclaim. It points to the knowledge, social networks, and privileged positions in the state that allowed the movement to have an outsized role in the policy process following democratic transition in 1992.