In this paper, we present a narrative review of primary research on the health impacts of extreme weather events in urban informal settlements published between 1990 and June 2021. We include 54 studies and examine the health impacts of extreme weather events and how these were determined. We find that these events impact health directly by causing mortality, injury and disease and through indirect pathways by impacting livelihoods, access to healthcare, coping strategies and adaptive capacity. Drawing on the social determinants of health framework to frame our analysis, we find that health impacts are determined by multiple intersecting factors, relating to individual circumstances, material conditions, health status, and political and socio-economic context. Consequently, vulnerability varies between and within informal settlements. Overall, we show that responding to and minimising these health impacts requires an intersectional approach to understand and address these contextual root causes of vulnerability.