Urban sustainability transitions have attracted increasing academic interest. However, the political-institutional contexts, in which these urban sustainability transitions unfold and by which they are incited, shaped, or inhibited, have received much less attention. This is why we aim at extending previous studies of sustainability transitions by incorporating a multi-level governance perspective. While multi-level governance has been a long-standing theme in political science research, it has remained under-explored in the study of sustainability transitions. This claim is the starting point of our comparative analysis of urban sustainability transitions in Brighton (UK), Dresden (Germany), Genk (Belgium) and Stockholm (Sweden). Our approach “brings the politics back in” by elucidating the dynamics of power concentration and power dispersion generated by different national governance contexts. In our analysis, we explore which opportunities and obstacles these diverse governance contexts provide for urban sustainability transitions.