Parents of young children with autism spectrum disorder (ASD) are more likely to experience high parental stress compared to other parents, and social support has been identified in previous research as an effective buffer against stress. However, limited research has evaluated the associations between different types of social support and stress in parents of young children with ASD, the possible impact of cultural background on parents' stress levels, and their use and experience of social support. The goal of this study was to examine the association between perceived, received, informal, and formal social support and parental stress level among U.S. and Chinese parents of young children (ages 0-6) suspected or diagnosed with ASD. Results showed that a high percentage of parents in both samples experienced high levels of parental stress: 81% in the U.S. sample and 96% in the Chinese sample. U.S. parents' (n = 64, mean age = 35 years) stress levels decreased as their perceived support increased. However, none of the four types of social support, individually or combined, were significantly associated with parental stress among Chinese parents (n = 45, mean age = 32 years). The results implied that ASD programs in the United States and China need to include parental stress as one of the foci of intervention. Additionally, due to the growing foreign and immigrant populations in the United States, ASD programs need to have a service delivery model that can accommodate to the needs of families with diverse cultural backgrounds. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]