Motor impairments are prevalent in children with neurodevelopmental disorders (NDD) and/or autism spectrum disorders (ASD) and often impact their development and quality of life. Early autism diagnosis can ameliorate lifetime outcomes by enabling earlier access to treatment. However, conventional clinical evaluation methods present some limitations due to high phenotypical heterogeneity within the autism spectrum and NDDs. Based on expanding research reporting high prevalence of motor impairments, there is a compelling need to develop quantitative methods to measure behavioral and motor-related phenotypes. Research focusing on gait analysis in individuals with ASD point to distinctive gait features. Thus, precise gait measures may contribute to more refined phenotype measures in NDD and ASD.This paper introduces the PediaSole, a minimally obtrusive insole-based system capable of measuring spatiotemporal gait parameters in pediatric populations. Accuracy of the system was validated against gold-standard equipment in neurotypical children and children with autism traits of genetic etiology, aged 3-12 yrs. Results indicated a good level of agreement between the PediaSole and the reference equipment. Additionally, 3 gait parameters (normalized stride velocity, stride time, and stance percentage) showed significant correlations with a well-established clinical measure of motor function, indicating the potential of this technology for clinical applications.