Autism spectrum disorder is a neurodevelopmental disorder that is characterized by impairments in social communication and social interactions along with repetitive, stereotyped behaviors and interests. The spectrum is quite broad, and the pathophysiology appears to be related to a number of factors. A common theme is that the disorder is one of impaired brain development. Neuroimaging studies offer a way to investigate impaired brain development by considering structural differences between those with autism and those without. Areas of focus include neuroanatomical regions that correlate with the clinically recognizable features of autism. In this review of structural studies, volumetric variation in terms of grey and white matter and total brain volume and in terms of neurological structures (e.g. frontal lobe, parietal cortex, amygdala, etc.) is discussed. Although a few trends have been noted, much of the literature demonstrates heterogeneity in the reported findings, which likely reflects the heterogeneity of the clinical presentation of this disorder. Further studies will need to correlate these structural findings with functional data and look to better understand the underlying molecular and genetic processes.