During the breakup of socialist Yugoslavia, the most violent conflict in Europe since 1945, children received extraordinary media attention as quintessential victims who played a vital role in nation-building processes in the successor states. This study analyzes the complex and thus far almost completely unexplored use of children and childhood in inculcating ethnonationalist ideologies among the youngest generation in those new polities. It considers two clashing ethnonationalist ideologies within Croatian territory in the first half of the 1990s: the national vision of newly-independent Croatia and opposing visions advanced by insurgent Serbs who proclaimed a parastate, the Republic of Serb Krajina, on about a third of Croatian territory, as part of a full-scale war that would last four years.Combining archival, media, and sociological analysis, the project explores how pro-regime media, national educational curricula, and selected outlets of children’s popular culture attempted to transform children into “ideal” Croats or Serbs, rejecting the old model of Yugoslav citizens raised on principles of interethnic harmony. I demonstrate that although the leaders of Croatia and the Republic of Serb Krajina did not create mass children’s organizations like the communists’ Pioneers, education and leisure activities continually stressed the role of children as vital constituents of the national collective, mirroring their importance in the former Yugoslav state. Even though deficits in state capacity hindered messaging in Serb Krajina, consistent efforts to implement educational programs from Serbia and inserting politically-charged content for Serb children in locally available media outlets suggests equal, if not even more radical campaigns to influence their hearts and minds by these ethnonationalist visions. Oral history findings, however, further complicate matters by showing the limitations of state capacity, especially in the educational sphere, to instill ethnically exclusive ideas of nationhood and patriotism in young citizens. Overall, these research findings also highlight significant continuities with Yugoslav socialist principles and practices, challenging traditional historical scholarship that tends to consider mass children's organizations as central to predominantly authoritarian societies. With regional and global significance, the project investigates the potential of media and new communication technologies to use and manipulate children to promote ethnic nationalism and other regime-driven political agendas.