The perpetration of severe inter-sibling violence (SISV) remains a largely unexplored area of family violence. This article describes an investigation of risk factors for intentional SISV perpetration. A sample of 111 young people under the care of the Scottish criminal justice or welfare systems was studied. A SISV perpetration interview schedule was developed to measure the influence of 43 potential predictor variables. The Buss and Perry Aggression Questionnaire and Levenson's Self-Report Psychopathy Scale were also employed in this exploratory analysis. (Contains 1 figure, 5 tables and 3 notes.)