In response to a dual crisis of legitimacy, ruling political elites in Thailand have, since the 2014 military coup, been engaged in a variety of initiatives aimed at reforming the relationship between the state and the Buddhist monkhood. These efforts were intensified after the death of King Bhumibol in October 2016 and the ascension to the throne by King Vajiralongkorn. Through amendments to the Sangha Act that invoke “ancient royal traditions,” repression of “corrupt” elements and disciplinary measures that separate monks from “worldly” affairs, the military-monarchical state has asserted domination over the ecclesiastical realm. These developments should be understood as part of a concerted effort to “purify” Buddhism ahead of the royal coronation, in which the Buddhist ecclesiastical hierarchy was employed to sacralise the new king and his reign. In a longer-term perspective, they represent an attempt to reverse the perceived hollowing out of the sangha and to restore institutional Buddhism to its historic role as a central pillar of political legitimation in the Thai political system. Sangha reform furthermore constituted the opening move in a post-Bhumibol game of politics that has amplified a neo-traditionalist and absolutist mode of monarchical government in Thailand and consolidated Vajiralongkorn’s power.