Both the ecological crisis and the policies set up to combat such crisis -pursuing the so-called green transition -are belonging to a 'third wave' of social risks after the ones connected to industrial and post-industrial transformations. We may label these new risks as 'socio-ecological risks'. Despite a growing number of studies attempting to build a bridge between the notions of social and environmental risks, a conceptual and analytical ambiguity is still prevalent in this emerging literature, preventing us to empirically define, identify and measure socio-ecological risks. Against this background, the paper has a threefold goal: first, it provides a definition of socio-ecological risks as significant changes in the magnitude and/or distribution of social risks, which occur directly because of climate change or other environmental hazards, and/or indirectly due to the distributive effects of environmental policies; second, it puts forward a theoretical model for the operationalization of this concept and the assessment of who is at risk, stressing the importance of four key elements: pre-existing vulnerability, exposure, dependency and eco-social policy mixes; and, third, it proposes a taxonomy to classify these risks, distinguishing between direct and indirect socio-ecological risks, and their social consequences, including income poverty, job losses, housing problems, issues of mobility, food insecurity, declining health and social exclusion. The paper relies on a thorough and critical literature review of established social science debates on social and then environmental risks, connected respectively to welfare state and environmental hazards studies. Aspiring to fill the gaps in the literature, the paper aims to advance a research agenda for the analysis of socio-ecological risks, which should guide future empirical studies in determining what are these risks and who is at risks.