The current diagnostic model for autism spectrum disorder (ASD) is largely based on behavioral evidence from structured observational assessments and parent interviews. Biomarkers for ASD have not been consistently replicated, and thus, there is a critical need to explore methods that can be used to support ASD diagnoses in an objective, rapid, and reliable manner. This study will investigate potential neurophysiological biomarkers through an examination of early-stage visual processing. Sensory processing abnormalities, specifically within the visual domain, are considered one of the most common associated symptoms of ASD. Visual symptoms are generally characterized by hyper- (e.g., sensitivity to bright lights) and hypo-sensitivities (e.g., visual inspection) that often directly impact social functioning. Sensory symptoms were incorporated into the proposed DSM-5 criteria for ASD, which highlights the importance of research in this area. While there is evidence to suggest that an underlying basic sensory problem may directly impact ASD symptoms, the majority of research has focused on later visual processes that are known to be associated with high-level perception; specifically, social-cognitive deficits, such as emotion, face, or object recognition/discrimination. A critical question remains as to whether higher-level social and cognitive dysfunction observed in ASD is a result of deficits in basic visual processing. This study uses visual evoked potentials (VEP) to identify neurophysiological biomarkers in a sample of low-functioning children with ASD, unaffected siblings, and controls. VEPs are a noninvasive technique, based on electroencephalographic recordings (EEG). The research training will emphasize visual neuroscience and phenotyping in the context of a multidisciplinary center with the aim of developing objective, rapid, and reliable biomarkers of ASD that can be used to support clinical diagnoses.