Criminal justice statistics show that Australia is the fourth highest nation for non-sexual violent assault and that most assaults are not random events. We investigated how grievances escalate into violence in a series of in-depth interviews with male maximum security prisoners who had a record of violent offences. Our analyses focused on the experience of grievance escalation and the justifications offered for the use of violence. We found that grievances were often triggered by psychological harm (broken promises, insults, inconsiderate behaviour) and that, although most of the men thought about the grievances only in terms of themselves and one other person, significant others, such as girlfriends or friends, on occasions provided weapons or encouraged violence. The involvement of significant others in escalating grievances suggests that violence prevention programs should include training in impression management and in skills to counter the insistence of girlfriends, family, and others for an aggressive response.