Background: Executive function is an assemblage of high-level cognitive domains (inhibition, working memory, planning, fluency, and shifting) that facilitate the inhibition of incorrect behaviors and the selection of appropriate behaviors according to context and goals. A deficit in cognitive shifting might be a core symptom of attention-deficit hyperactivity disorder. However, previous studies addressing this issue used neurobehavioral tests, which might not be specific enough to measure cognitive shifting. The purpose of the present study was to compare cognitive shifting among children with attention-deficit hyperactivity disorder and typically developing children using a Dimensional Change Card Sort task while simultaneously measuring patterns of neural activity in the prefrontal cortex. Methods: We recruited 22 children diagnosed with attention-deficit hyperactivity disorder and 37 typically developing children as controls matched on age, gender, language ability, and non-verbal intelligence quotient. Participants performed the computer-based Dimensional Change Card Sort task, while prefrontal cortical activity was measured with near-infrared spectroscopy. Results: Children with attention-deficit hyperactivity disorder exhibited more incorrect answers, similar reaction times, and less prefrontal activity as compared to the typically developing children. Conclusion: The Dimensional Change Card Sort task results revealed deficits in cognitive shifting among children with attention-deficit hyperactivity disorder. This was particularly observed through the appearance of several performance errors and with decreases in prefrontal brain activity.