The objective of this narrative review is to analyze, through the estimates made in previous studies, the costs of medical, physical, and mental care, productivity losses, costs for the child protection system, and costs for the criminal justice system of violence against children and youth, with special emphasis on sexual violence. The reviewed studies confirm that violence in early stages of development is associated with greater use of health services and other resources, which represents a significant public investment that must be taken into account. These works have limitations that derive from the incomplete or unreliable data included regarding mortality and morbidity related to violence against children and that imply variable estimates of their costs, which in Spain range from 17 billion euros for adverse childhood experiences, to around €1 billion for sexual violence. Reliable data are needed on the costs of violence against children in order to make better-informed decisions about financial investment in its prevention and treatment, as well as to raise awareness of its scale and impact.