The Scottish Child Abuse Inquiry (SCAI) commissioned the research project to document the outcomes of institutional abuse in long-term child care in Scotland. To profile the experiences of survivors abused in long-term child care in Scotland, and to develop a model which linked maltreatment, risk and protective factors, and outcomes. 225 survivors of historical institutional abuse in Scotland, who made witness statements to SCAI. Data were extracted from witness statements using a coding frame developed through a thematic analysis of a subsample of 52 statements. Survivors had been in care in predominantly Catholic and non-religious residential institutions in Scotland for an average of 8 years, having entered at an average age of 6.8 years. They had suffered multiple forms of maltreatment. Maltreatment rates were: physical abuse, 95.6%; emotional abuse, 85.3%; sexual abuse, 60.4%; emotional neglect, 51.1%; and physical neglect, 37.3%. Across the lifespan survivors had negative outcomes in psychosocial adjustment (96%), mental health (84%), and physical health (43%). The effect of maltreatment in care on psychosocial problems was mediated by both risk and protective factors; and on mental health was mediated by risk factors, but not protective factors. Maltreatment in care had a direct effect on physical health which was not mediated by risk or protective factors. The effects of the cumulative number of risk factors on adverse mental health and psychosocial outcomes was greater than that of maltreatment, and protective factors had a limited impact on adverse outcomes. Evidence-based child protection policies and practices should be implemented to prevent institutional abuse and treat child abuse survivors in Scotland.