Given the critical shortage of community providers and a growing aging population of individuals with intellectual and developmental disabilities, siblings are expected to provide caregiving for their brothers and sisters with intellectual and developmental disabilities. However, family support and disability policies often do not acknowledge siblings as caregivers who need support, and thus, do not include siblings' voices. In this study, we conducted a U.S. national, web-based survey to examine the perspectives of 611 siblings of individuals with intellectual and developmental disabilities. Specifically, we examined their perceptions toward family support and disability policy as well as their knowledge and relevance of such legislation. Overall, siblings were not well-informed with relevant family support and disability policies. Furthermore, the knowledge of policies was only associated with their feelings of connectedness to the disability community. Based on these findings, it seems necessary that siblings are included in future efforts to shape family support and disability policy.