Background Attention-deficit hyperactivity disorder (ADHD) is a common neuropsychiatric syndrome with onset in childhood, most commonly becoming more apparent during the first few years of grade school. The aim of this study is to assess peripheral hearing and central auditory processing as well as cognitive function in 30 children diagnosed with ADHD. Their age ranged from 6 to 16 years (16 males and 14 females) and their IQ of at least 70. All of them were subjected to a basic audiological evaluation, and assessment of auditory brainstem responses, slow vertex response, and P300 waves using the oddball paradigm. Results No significant differences were found between pure tone thresholds and speech audiometry between the study and the control groups. There was a statistically significant increase in auditory brainstem response (ABR) absolute latencies (III and V) and interpeak latencies (I–III and I–V) at both low repetition rate and high repetition rate. Also, an increase in latencies of N1, P2, N2, and P300 latencies was observed with decreased P300 amplitude of the study group compared with the control groups. A significant mild positive correlation was found between P300 and both wave V latency and I–V interpeak latency. Conclusion The results of this study provide more evidence of central auditory processing involvement in children with ADHD and show the role of ABR and P300 in the management of these children.