Background Due to long waiting lists for services, many adults with intellectual and developmental disabilities in the United States have unmet service needs. Little research, however, has identified the characteristics of caregivers and individuals with intellectual and developmental disabilities that relate to the unmet service needs among individuals who are waiting for services. Method The present authors conducted a statewide mail survey of 234 caregivers of individuals with intellectual and developmental disabilities who were waiting for services. The present authors identified which parent and individual with intellectual and developmental disability characteristics were significantly associated with the number of unmet service needs. Results Individuals with intellectual and developmental disabilities who were in poor health, from minority backgrounds and non‐verbal were significantly more likely to have a greater number of unmet service needs. Additionally, individuals with younger caregivers and individuals with caregivers from low‐income backgrounds were significantly more likely to report a greater number of unmet service needs. Discussion Implications for research and policy are discussed.