Parent-mediated interventions (PMI) are increasingly being used to target skill deficits in children with Autism Spectrum Disorder (ASD). Evidence documenting the benefits of PMI is accumulating, however, little is known about whether parent characteristics impact children's treatment outcomes. We reviewed the PMI literature using PRISMA guidelines to address this gap. We identified 115 PMI studies published between 1987 and September 2018; of these, only 11 examined the contributions of baseline parent/caregiver characteristics on children's outcomes. These studies vary widely in regard to the interventions employed and outcome measures explored. Early intervention programs were the most common form of treatment and stress was the most frequently targeted parent/caregiver characteristic. Results indicated that stress, socioeconomic status, and the broad autism phenotype may be related to children's outcomes, with varying effects depending on the specific treatment and outcome examined. These results underscore the need for systematic research on the role of parent baseline characteristics in PMI. A deeper understanding of the relationship between parent/caregiver variables and child outcomes may inform treatment selection and elucidate key mechanisms of therapeutic change.