We conducted a systematic review and summarized the outcomes of single-case research design studies conducted in the last decade that have implemented peer-mediated interventions (PMI) to address the social competence needs of children with autism spectrum disorder (ASD) younger than 8 years of age. Eighteen studies with 53 children with ASD were included. Data from those studies were extracted independently by two coders and coded for characteristics of children with ASD, characteristics of peers, characteristics of the intervention, risk of bias, and success estimate. Findings suggest that PMI are effective for increasing interactions between children with ASD and peers but may not be as effective for increasing initiations made by children with ASD or increasing responses made by children with ASD to peers' initiations. Researchers should prioritize conducting studies that seek to promote positive interactions initiated by children with ASD, possibly by modifying PMI to include preferred stimuli identified through systematic assessments.