What role do organizations play in the enactment of large-scale violence against a specific group of people? In this paper, I depart from existing literature that focuses on violence within organizations, and instead emphasize the influence of external actors. Specifically, I examine the ways in which supporting organizations can first legitimate, and then actively maintain, violence against a group of vulnerable people. Drawing upon a unique, recently-published archive of data, these ideas are developed through an analysis of a case study in which large-scale violence was carried out on a vulnerable group: Ireland’s industrial school children. I draw on Kristeva’s notion of abjection to show how an excluded, distasteful ‘other’ is discursively co-constructed such that violence is seen as acceptable, and then actively maintained in the abject position as a boundary object that encompasses shared meanings across different organizations. Contributions include a framework for understanding the role of organizations in the perpetration of large-scale violence, which highlights how violence can be legitimated via the construction of subjects as abject boundary objects in extreme cases, and how this abject position can be maintained through inter-organizational dynamics comprising excessive rules and regulation, the suppression of care, and active policing. Finally, scholarship on boundary objects is extended by this paper’s interrogation of the ‘dark side’ of this inter-group phenomenon, an area that is rarely studied.