Intellectual disability is a serious lifelong disability that places heavy demands on society and the health system. The study was designed to determine the extent to which the intellectually challenged children are capable of improving their cognitive abilities as well as adaptive functioning through the Montessori Sensorial Training program when introduced in a different setting (i.e. special education school system). With randomised control trial (RCT) of pre-and post-testing, 30 children with mild intellectual disabilities were randomly allocated to Montessori Sensorial Training intervention condition (n = 15) and waitlist control condition (n = 15). The intervention group showed significant improvement in cognitive abilities (i.e. classification, seriation, recognition, ordination, and visual and auditory discrimination) as compared to the control group at post-assessment. Children who received training also showed improvement in communication and self-care domain as compared to the control group. This study provides evidence that Montessori Sensorial Training is not only effective for children going to mainstream schools but also for children with intellectual disabilities. Despite some limitations, the results of the study are encouraging and suggesting that Montessori Sensorial Training is an effective intervention to facilitate self-based learning, independence, and decision-making skills in children with mild intellectual disabilities.