This discussion explores energy policymaking in Southeast Asia, focusing on Indonesia, Malaysia, the Philippines, and Thailand. These countries represent a diversity of energy resources and potential for economic-political transformation. In the past three decades, there have been major shifts in energy policy regimes, and the transition in energy policymaking involves distinct temporal and developmental phases, coinciding with structural transformation that accompanied economic development and external crisis. An exploration of the dynamics of arrangements and relationships between formal and informal policymaking institutions and actors adds important lessons for policymaking. We highlight the prominence of a regional cooperation agenda, which will continue to be relevant as the region actively engages with other countries to meet commitments under the Paris Agreement.