This chapter presents an empirical study examining the relationship between environmental stress and rural–urban migration in northern Ethiopia. It begins with an exploration of the evolution of the debate on ‘environmental refugees’, arguing that, more than anything else, this debate has constituted a battle for discursive legitimacy. From this perspective the chapter uses case studies from northern Ethiopia to show that mobility forms an important social response to environmental stress, but notes that it does so because of the socio-political and economic context in which such stress occurs, rather than in spite of it. To this end case studies from northern Ethiopia will be used to challenge the conception of migration as a failure to adapt and/or as a strategy inevitably pursued at the end point of vulnerability. In so doing the chapter will argue that migration represents a strategic livelihood option, only enacted when the contexts (social, economic, and political) structuring other livelihood options mean that it makes sense to do so. Here the chapter will argue for the politicization and historical location of mobility decisions taken in a context of environmental stress. Specifically the chapter argues that it is micro-scale, socio-political, and economic contexts which determine whether migration is enacted in response to the imperatives generated by macro-scale processes of environmental stress. The chapter closes with a reflection on the implications of these findings for policy.