This article explores the differences between the vulnerability of two ethnic minorities faced with the same environmental disaster, along with the causes of those disparities. Set in the context of the degradation of Lake Urmia in north-western Iran, the study problematizes the unequal access to political power of the Kurdish and Azeri minorities and the historical dynamics of marginalization and empowerment. It links those dynamics with the current differential vulnerability of the members of the two minorities living in proximity of the lake, who have traditionally been dependent on agriculture as a means of subsistence. The degradation of the lake has severely affected the agricultural production in the region through the salinization of irrigation water and the degradation of arable land. The study focuses on households in the proximity of the lake with the goal of exploring to what extent their ethnicity determines their vulnerability and adaptive capacity in the face of the disaster. We find that ethnic politics plays a role in the access to irrigation water and the potential for income diversification, as well as being a component of the coping capacity embedded in social networks. Additionally, we find that ethnicity is a determinant of the availability of economic resources, and strongly influences the knowledge of – and willingness to participate in – governmental and non-governmental projects to mitigate the effects of the environmental disaster.Key words: vulnerability, ethnicity, Iran, political power, minorities, environmental degradation, Lake Urmia