Williams syndrome, Autism and ADHD are three neurodevelopmental disorders sharing some developmental deficits and varying in others. The aim of this study was to specify the auditory phenotype in terms of the peripheral and central hearing abilities through the utilization of different assessment methods, objective and subjective ones, in order to identify these alterations in the central and peripheral auditory systems especially when we consider the existence of language and cognitive alterations because hearing alterations can compromise language acquisition and normal development, as well as the entire rehabilitation process. All cases were subjected to detailed peripheral hearing assessment in addition to speech and click evoked ABR and P300 measurements. Results showed impaired subcortical encoding of speech and abnormal P300 results which were most explicit in the autistic group. In conclusion least severe deficits in auditory processing of speech stimuli were identified in the WS group. We concluded that differences in the auditory profiles could be encountered when comparing the three neurodevelopmental groups and some of these findings are suggested to be matching their social and behavioral differences.