This article is concerned with White Armband Day (Dan Bijelih Traka), marked on 31 May in memory of the genocidal campaign against Prijedor’s non-Serb population during the war in Bosnia-Herzegovina (1992–95). What started spontaneously in 2012 as a global social media campaign against genocide denial has become a commemoration day marked in Prijedor, the post-Yugoslav region, across the world and in virtual spaces. Its widespread recognition and impact on alternative memory discourses rendered it one of the most successful civil society initiatives engaging in dealing with the past in the region. Drawing on a transnational mobilisation perspective, the article explores how the initiative emerged and what factors contributed to White Armband Day’s establishment as a transnational commemoration day. Findings from multi-sited research indicate that beyond rapid online mobilisation, two prerequisites have been key to its success: displacement-based (trans)local networks of Prijedorčani and its ability to mobilise young people across ethnic divisions.

本文与“白色臂章日”有关（Dan Bijelih Traka），纪念5月31日在波斯尼亚和黑塞哥维那战争期间针对Prijedor的非塞族人的种族灭绝运动。自2012年作为反对种族灭绝的全球社交媒体运动而自发开始，如今已成为纪念日，纪念日在南斯拉夫后大区普里耶多尔，全球以及虚拟空间中进行。它被广泛认可并影响了替代性记忆的话语，使其成为处理该地区过去历史的最成功的民间社会倡议之一。本文从跨国动员的角度出发，探讨了该倡议的产生方式以及促成怀特臂章纪念日成立为跨国纪念日的因素。多地点研究的结果表明，除了快速的在线动员之外，