Individuals with autism spectrum disorders (ASD) exhibit early and lifelong impairments in attention across multiple domains. While the disorder is known to affect attention processes, very little is currently known about the brain networks underlying attention in ASD, and even less is known about whether these atypicalities persist across the lifespan. We used functional connectivity analysis applied to resting state functional magnetic resonance imaging (fMRI) data to explore the dorsal (DAN) and ventral (VAN) attention networks in two separate age cohorts of children and adults with and without ASD. We find significant developmental differences in functional connectivity of brain regions that are critical for attention in children and adults with ASD. Specifically, children with ASD show hyper‐connectivity of regions‐of‐interest (ROIs) in both attention networks compared with both typically developing (TD) children and adults with ASD. In contrast, adults with ASD show hypo‐connectivity of these networks compared with neurotypical adults. These findings are consistent with the notion that consideration of developmental stage is critical in studies of functional connectivity in ASD. This study further illustrates diverging developmental patterns for top‐down and bottom‐up attention systems in autism. Individuals with autism exhibit a variety of deficits in attention processes, yet brain networks supporting attention in autism have not been systematically investigated. We examined functional connectivity of dorsal and ventral attention networks in children and adults with autism and found that compared with neurotypical individuals, functional hyper‐connectivity is observed in children with ASD, whereas functional hypo‐connectivity is observed in adults with the disorder.