IntroductionClimate change poses critical risks to urban areas due to their dense populations and infrastructures that are sensitive to climatic conditions. As cities grow rapidly, their exposure to climate and disaster risks increases, highlighting their critical role in climate change adaptation. Urban heat disproportionately impacts informal settlements in low- and middle-income countries (LMICs). These communities often lack essential infrastructure, adequate housing, and green spaces, further increasing their vulnerability during extreme heat events. Despite their heightened risk, the voices and needs of at-risk populations are frequently excluded from urban heat adaptation strategies. This rapid review investigates the current state of knowledge about ethical considerations regarding the participation of at-risk groups in urban heat adaptation in LMIC, with a particular focus on informal settlements.MethodsA rapid review was conducted to synthesize evidence from peer-reviewed studies on urban heat adaptation in LMICs. Cochrane rapid review guidelines were followed, with searches performed in Web of Science, PubMed, and SCOPUS. Out of 227 studies screened, 30 were included in this review. The included studies address heat adaptation in LMICs and are published in English between January 1, 2000, and the search date. Non-peer-reviewed and non-English articles are excluded. Thematic analysis guided by a disaster justice theory framework was applied to identify key findings related to ethical considerations and the inclusion of vulnerable groups in adaptation planning.ResultsThe dimensions Accountability, Representation, Knowledge, Platform, and Agents of Change of the disaster justice framework were scarcely addressed in the included studies. Only Conviction was mentioned in most cases. Our findings indicate that the equitable distribution of heat adaptation resources is insufficient and accountability mechanisms are nearly absent. Moreover, marginalized groups and their knowledge are rarely recognized in official decision-making processes. There is a lack of spaces in which various stakeholders and dwellers of informal settlements can engage in dialog and participate in joint decision-making. However, the included studies advocate with ethical conviction for prioritizing the needs of vulnerable groups.DiscussionStudies consistently report weak or absent accountability mechanisms and limited representation of marginalized groups, particularly women, in adaptation governance. Although residents rely on culturally rooted and contextually informed heat-adaptation practices, such local knowledge is rarely acknowledged or integrated into formal planning. Participatory platforms remain scarce, with only isolated examples of collaborative decision-making. Identified agents of change—including researchers, women, brokers, and local experts—advocate for marginalized communities, but these efforts lack structural support. Most studies nevertheless demonstrate a strong ethical conviction, recognizing heightened vulnerabilities and calling for more just adaptation processes. Given the persistent undervaluation of local knowledge and the limited inclusion of vulnerable groups in decision-making, we advocate for the formal incorporation of justice-oriented frameworks into urban heat adaptation planning to promote equitable, community-centered responses. These findings are meant to contribute to the creation of equitable adaptation strategies, that not only mitigate the impacts of extreme heat but also strengthen the resilience of at-risk populations.Systematic review registrationhttps://doi.org/10.17605/OSF.IO/SHKE2