Sensory processing has long been a topic of interest in the field of occupational therapy. This study sought to replicate the results of Davies and Gavin (2007) which examined differences in auditory sensory processing between children with sensory processing disorder (SPD) and typically developing (TD) children as well as expand the results to a sample of children with high functioning autism spectrum disorder (ASD). Additionally, this study sought to relate the neurophysiological measures of sensory processing to a behavioral assessment measuring sensory processing. We hypothesized that the results of Davies and Gavin (2007) would be replicated and expanded to include children with ASD and measures from the Sensory Profile (SP) would relate to the participants' neurological measures of sensory processing. 62 TD children, and 21 children each with SPD and ASD were recruited as part of a convenience sample. Participants’ brainwaves were recorded through electroencephalography (EEG) while they watched a silent movie and listened to a sensory gating paradigm consisting of two paired clicks and a sensory registration paradigm consisting of 4 tones of varied intensity and frequency. From the sensory gating paradigm P50 amplitudes were obtained. From the sensory registration paradigm amplitudes and latencies for N100, P200, N200, and P300 were obtained. Analyses revealed that while the results of Davies and Gavin (2007) were partially replicated, in that sensory gating was able to be significantly predicted from sensory registration the same pattern of sensory hyper and hypo-responsivity was not observed. Results indicate that the Sensory Profile does in part relate to the neurophysiological measures of sensory processing. This study confirmed that auditory sensory processing does differ between children with SPD, children ASD, and TD children. It contributes to occupational therapy's understanding of sensory processing in children and also towards increased understanding of how the SP relates to underlying neurological mechanisms.