Autism spectrum disorder (ASD) is a developmental disorder that warrants early intervention. This systematic review evaluated the efficacy of parent-mediated natural developmental behavioral interventions (NDBIs) for children aged 0–6 with ASD across various randomized controlled trials (RCTs) and explored the limitations of these interventions. A systematic search was conducted across the PubMed, Web of Science, Embase, and Scopus databases to identify RCTs, and the selected studies were assessed for quality. The search was conducted through January 2024 and identified eight RCTs that, despite varying methodological rigor, collectively suggest benefits for social communication, language skills, and parent‒child interactions in individuals with ASD. Future research should implement standardized intervention protocols, employ sensitive assessment tools, and provide detailed statistical analysis plans to improve the generalizability and reliability of the outcomes of this study.