Parent-mediated interventions (PMIs) are commonly used with children with autism spectrum disorder (ASD), and their effectiveness for young children has been documented. However, no reviews have examined the use of PMIs with older children with ASD. Therefore, the purpose of this review is to investigate the state of the literature regarding PMIs for school-age children with ASD and to evaluate their effectiveness across domains. Eighteen studies of PMIs examining 170 child participants with ASD were included. Participants, interventions, and the effects of the interventions are described. Overall, studies demonstrated moderately positive effects for PMIs for school-age children with ASD. Group design studies demonstrated an overall effect size (ES) of 0.79, 95% confidence interval (CI) = [0.50, 1.09], while single-case design (SCD) studies yielded an overall ES of 1.84, 95% CI = [1.08, 2.60]. More research is needed to understand the differential effectiveness of parent training components, and future research should focus on including measures of parent treatment integrity, to aid in the understanding of program efficacy.