Southeast Asian governments have maintained “energy self‐reliance” and “energy security” as essential rationales of their macroeconomic policy. Since the availability of energy remains necessary for unabated domestic growth and development, the pursuit for “alternative” sources of energy and the resolve to build sustainable energy systems are constant priorities. Informed by the literature on policy discourse, this article draws attention to the analytical use and significance of policy discourse as a means to examine sustainable energy policies in Southeast Asia, which dominantly adopted an economic lens for “energy supply security.” Policy documents were examined to show the congruence and variation of policy discourses that prompted the governments of Indonesia, the Philippines, and Singapore to institutionalize sustainable energy development from 2000 to 2016—a critical period for the institutionalization of sustainable energy in the region, when domestic renewable energy sectors and systems were simultaneously being established by these governments.