Introduction: Autism spectrum disorder (ASD) is a neurodevelopmental condition which often begins in early childhood and can involve a spectrum of persistent challenges with social communication, restricted interests, and repetitive behaviours. Literature in western and non-western countries has demonstrated that parents of children with ASD experience elevated stress relative to parents of neurotypical children. Despite the health-related burdens presented by raising children with ASD, little clinical and research emphasis is placed on reducing parental stress. Furthermore, much of the limited work on parent-centered interventions been conducted in the U.S., and few similar interventions have been developed for the Japanese population. Methods: The Japanese Parent Mentorship Program (JPM) seeks to modify a pre-existing social support intervention (the Colorado Parent Mentorship Program developed for parents of ASD children in the U.S.) to Japanese parents by incorporating dialogue about the culturally relevant stressors, social acceptability, maternal burden, saving the face, and parent-child attachment. To test the efficacy of the JPM at reducing parental stress, a randomized control trial will be conducted with mothers of ASD children who were born and are living in Japan for a minimum of five years. Results: Enrolment into the JPM will be associated with decreased parental stress post-intervention. The social support provided in the JPM will also be a protective moderator on the relationship between parental stress and ASD severity by weakening the overall association between parental stress and ASD severity. Discussion: The JPM can improve health outcomes for parents and their children with ASD by decreasing parental stress and consequently, ASD severity, leading to numerous indirect and positive implications on their physical, emotional, and social well-being. As prompted by the JPM, cultural competence in ASD management, is associated with positive outcomes such as such as increased likelihood of treatment continuation, increased strength of perceived therapeutic alliance and increased perceived treatment benefit. Conclusion: This research contributes to a major gap in the cross-cultural literature about parental stress and ASD. This work can be used to inform intervention strategies in Japan and researchers can emulate this design towards a global shift of providing culturally competent interventions for all.