Southeast Asia is endowed with immense potential in sustainable energy sources, and the need to leverage renewable energy is underpinned by increasing energy demand and climate commitments. The region's energy transition, however, is riddled with various challenges. This paper argues that Southeast Asia suffers from carbon lock-in, which occurs when fossil fuel technologies, markets, and institutions co-evolve and become structurally linked, making the energy transition inert. The research focuses on three Southeast Asian countries driving the expansion of fossil-fuel production in the region: Indonesia, the Philippines, and Viet Nam. Using Trencher et al.'s socio-technical framework on carbon lock-in (2020), the paper answers two key questions: (1) What are the sources of carbon lock-in in Indonesia, the Philippines, and Viet Nam and (2) What are the available opportunities that can rupture carbon lock-in? A scoping review was conducted using 183 publications comprised of journal papers, practice-based reports, news articles, and government documents. Using content analysis, the scoping review produced 31 sources of carbon lock-in ranging from material factors, human actors, non-material factors, and exogenous factors; and 21 key opportunities for a low-carbon pathway for Indonesia, the Philippines, and Viet Nam.Southeast Asia is endowed with immense potential in sustainable energy sources, and the need to leverage renewable energy is underpinned by increasing energy demand and climate commitments. The region's energy transition, however, is riddled with various challenges. This paper argues that Southeast Asia suffers from carbon lock-in, which occurs when fossil fuel technologies, markets, and institutions co-evolve and become structurally linked, making the energy transition inert. The research focuses on three Southeast Asian countries driving the expansion of fossil-fuel production in the region: Indonesia, the Philippines, and Viet Nam. Using Trencher et al.'s socio-technical framework on carbon lock-in (2020), the paper answers two key questions: (1) What are the sources of carbon lock-in in Indonesia, the Philippines, and Viet Nam and (2) What are the available opportunities that can rupture carbon lock-in? A scoping review was conducted using 183 publications comprised of journal papers, practice-based reports, news articles, and government documents. Using content analysis, the scoping review produced 31 sources of carbon lock-in ranging from material factors, human actors, non-material factors, and exogenous factors; and 21 key opportunities for a low-carbon pathway for Indonesia, the Philippines, and Viet Nam.