The act of telling one’s story in a post-conflict setting — whether as a witness testifying in a criminal trial, recounting events before a truth commission, or speaking up at a community meeting — demands resolution and courage. This chapter explores the role testimony plays in transitional justice processes after mass violence. Psychological, social, and political factors, as well as the nature of the violence itself, influence witness testimony and memorialisation. Collective memories of violence evolve as societies pass through processes of social reconstruction and community reckoning. The chapter provides guidance to court investigators and researchers about the complexities of survivors’ testimonies and the risks and ethical obligations of doing fieldwork in post-conflict settings.