This thesis examines the occurrence and spread of contentious collective action within a country, Bosnia Herzegovina, that historically does not bear a solid tradition of mobilization. In particular, the study focuses on the rise of mobilizations that transcend traditional ethno-nationalist cleavages, and involve individuals and groups that activate an identity other than the ethno-national one, still dominant in the Bosnian Herzegovinian society. I adopted the expression “beyond ethnicity” to label this type of mobilization, stressing that individuals and challenger groups involved in the protest overcame the centrality of ethnicity as social construct, privileging another commonality between individuals that deliberately superseded, and sometimes clashed with, the dominant ethno-national categories that had crystallized in the 1990s. This new, overarching identity is often grounded on feelings of deprivation. Informed by a five-year empirical research in the country, the study explores the variation in spatial and social scale of contention across three waves of mobilization that occurred between 2012 and 2014 and took divergent paths, despite similar socioeconomic structural conditions. Through a comparative case study approach, the thesis analyses three waves of protests, taken as manifestations of “mobilization beyond ethnicity”: “The Park is Ours” protests (2012), spawned from the defence of a public park of Banja Luka; the mobilization for civil rights of the children, which became known as #JMBG (2013); and the protests that erupted in Tuzla triggered by local workers, which turned into what activists defined as a “Social Uprising” (2014). The study explains why the waves of mobilization occurred between 2012 and 2014 spread unevenly across the national territory, involved diverse social groups, and entailed different degrees of disruption. The findings of this research demonstrate that a combination of factors both internal and external to the movements made the territorial and social shift upward more likely, and influenced the organizational patterns and action repertoires of the challengers. These factors are pre-existing networks among movement organizers; the resonance of “beyond ethnic” frames in certain cultural milieus; and a conducive political opportunity structure. In the conclusions, the thesis elucidates the implications of these findings for the study of social movements in the post-Yugoslav space.