Urban political ecology (UPE) can contribute important insights to examine traffic congestion, a significant social and environmental problem underexplored in UPE. Specifically, by attending to power relations, the production of urban space, and cultural practices, UPE can help explain why traffic congestions arises and persists but also creates inequalities in terms of environmental impacts and mobility. Based on qualitative research conducted in 2018, the article applies a UPE framework to Bangkok, Thailand, which has some of the world's worst congestion in one of the world's most unequal countries. The city's largely unplanned and uneven development has made congestion worse in a number of ways. Further, the neglect of public transport, particularly the bus system, and the highest priority given to cars has exacerbated congestion but also reflects class interests as well as unequal power relations. Governance shortcomings, including fragmentation, institutional inertia, corruption, and frequent changes in leadership, have also severely hindered state actors to address congestion. However, due to the poor's limited power, solutions to congestion, are post-political and shaped by elite interests. Analyses of congestion need to consider how socio-political relations, discourses, and a city's materiality shape outcomes.