Limited information about self-injurious behavior (SIB) is known for children and adolescents with Autism Spectrum Disorder (ASD) who require intensive behavioral health interventions. We examined risk-factors for SIB in 302 individuals with ASD (ages 4-20) admitted to six specialized psychiatric inpatient units. Seventy-four percent were reported by a caregiver to display SIB, however, only 25% were observed to engage in daily SIB during hospitalization. Those exhibiting SIB across environments had significantly higher ratings on caregiver questionnaires of SIB severity. Tree-structured classification was used to develop and validate two predictive models, one indicating which inpatient youth with ASD are likely to have SIB and a second indicating which individuals with SIB at home are likely to continue in an inpatient setting.