Compared to adults without disabilities, individuals with intellectual and developmental disabilities (IDD) are more likely to experience social victimization. This study examined responses of caregivers of 146 adults with IDD on questionnaires concerning demographics and behavioral characteristics as well as a newly developed Social Vulnerability Questionnaire (SVQ). Demographic and behavioral characteristics were related to risk factors of vulnerability. Caregivers provided examples of victimization experienced by individuals with IDD throughout the life span. Examples related to money/theft, teasing/persuasion, and abuse. Findings indicate that although individuals who are higher functioning are more aware of vulnerable situations, they still experience victimization at rates similar to those who are less able to detect risk. Those who were rated as more vulnerable displayed more externalizing behavior problems. Implications for research and practice are discussed; research is needed to understand the risk factors of victimization and interventions are needed to teach self-protection skills. (Contains 5 tables.)