Naturalistic developmental behavioural interventions are promising approaches for young children with, or suspected of having, autism spectrum disorder. Joint attention, symbolic play, engagement and regulation intervention (JASPER) is a well-researched naturalistic developmental behavioural intervention but, to date, no reviews have specifically evaluated its effects. This systematic literature review examined the effects of JASPER intervention and its components on child, parent and educator outcomes. Of the 96 articles screened, 19 were eligible for inclusion in the review. Most studies found that children who received JASPER intervention showed significantly greater improvements in at least one outcome related to child joint attention, joint engagement, play skills and language skills compared to the comparison group. Implementation outcomes for parents and educators were generally positive. There were no consistent predictors or mediators of treatment effects. None of the studies met all of the quality indicators outlined by the Council of Exceptional Children, and the majority of outcome measures were classified as proximal. Overall, JASPER intervention appears promising in improving child outcomes directly targeted during treatment. More research is needed to determine whether it is also effective in improving a wider range of outcomes for children with autism spectrum disorder.