The advent of functional neuroimaging and its flourish have played a critical role in elucidating differences in the ASD brain. While research on functional activation in ASD has been abundant and illuminating, the increased reliance on focal brain regions has been inadequate in understanding ASD due to limited consistency of findings. In recent years, neuroimaging research has largely shifted to examining the brain at a network level. Functional connectivity research has lent way to the disrupted connectivity hypothesis, which postulates that ASD is a distributed disorder marked by inefficiencies in the synchronization of brain activity. In particular, there is cortical underconnectivity of long-distance connections, coupled with local overconnectivity. The pursuit of sensitive and accessible biomarkers remains at the forefront of research efforts, and disruptions in functional connectivity are emerging as a potential future tool for assessing risk, classifying symptom presentation, and determining treatment response and prognostic status.