Life course health development (LCHD) incorporates theories and empirical evidence from the biological, physical, and social sciences to formulate a framework that explains how health develops over the life course. The life course health development conceptual framework can be applied to autism spectrum disorders (ASD) to help prioritize a research agenda and improve health development across the lifespan for individuals with ASD, their families, and communities. The following chapter highlights some issues and findings that are pertinent to an understanding of ASD using the lens of the life course health development principles. The chapter begins with a description of the clinical phenotype, followed by epidemiology of the disorder, and reviews changes in classification and diagnosis over time. Pathogenesis of the disorder is discussed, including information pertaining to hereditability, genetic and nongenetic factors, epigenetics, biomarkers, and genotype-phenotype correlations. Long-term follow-up outcome studies of adult independence and quality of life are reviewed, including examination of predictors of outcome, as well as stability of the diagnosis, symptom presentation, and cognitive functioning over time. Areas of key transitions over the life course are discussed from childhood to later adulthood. In addition, the importance of mental health status and care are highlighted. Finally, a number of research, data/methods, and translational priorities are offered that may help lead to a better understanding of life course health development in ASD.