Increasing evidence suggests an association between childhood obstructive sleep apnea (OSA) and metabolic syndrome, with more research available on the potential impacts of positive airway pressure (PAP) on metabolic markers in children. The purpose of this systematic review is to provide a systematic synthesis of the evidence on the effect of PAP use on metabolic markers in children with OSA. A search strategy with terms for "OSA" and metabolic markers in pediatrics was run to systematically assess 5 databases until August 26, 2022. Two reviewers independently screened eligible articles, extracted data, and conducted quality appraisal. Meta-analysis was done using random-effects models. Body mass index (BMI), glycemic, lipid, cardiovascular, and other metabolic and inflammatory markers were reported. Sixteen studies (N = 1,213) were included, 15 observational studies and 1 randomized controlled trial (RCT); most reported outcomes in children with obesity. Meta-analysis of 4 studies found no changes in BMI at median average follow-up of 12 months after PAP initiation. A reduction in heart rate and blood pressure parameters was demonstrated in several studies in children with OSA with and without obesity at a median average follow-up of 4.9 months after PAP initiation. Research in echocardiographic outcomes is limited, including one RCT in children with Down syndrome and OSA showing no changes in heart rate variability parameters. Evidence of improvements in glycemic and/or lipid control, liver enzymes, and inflammatory markers with PAP therapy is even more limited and of limited clinical importance. Risk of bias was moderate to critical and outcome evidence very low. Although evidence on effects of PAP on metabolic markers in children with OSA is encouraging, available literature is limited. Longitudinal studies are still required to further assess the long-term influence of PAP on metabolic and inflammatory markers, particularly in children with obesity.