Objective: Traditional and non-traditional strategies have been employed to improve youth health. Dog-assisted interventions have been proposed as a novel strategy to regulate stress and its consequences across all age groups. This systematic review and multilevel meta-analysis assessed the influence of dog-assisted interventions on cortisol levels in youth and explored potential moderators. Sources: We conducted a comprehensive systematic search across multiple databases, including PubMed, Scopus, Web of Science, Cochrane Library, and ScienceDirect, up to June 17, 2024, to evaluate the impact of dog-assisted interventions on youth cortisol levels. Two reviewers independently extracted and verified data from eligible randomized clinical trials, with a third reviewer ensuring accuracy. Cochrane's RoB 2.0 tool was used to assess the risk of bias. Heterogeneity was analyzed using Q and I2 statistics. A random-effects model was employed to calculate effect sizes (ES) using R software. Summary of the findings: Significant cortisol reductions were found for interventions lasting >15 min (ES: 0.65; p = .038), with a non-significant trend towards reduced cortisol in non-medical settings (ES: 0.46; p = .070). No significant effects were observed for shorter interventions, different control groups, or age-specific analyses. Meta-regression analysis revealed significant differences, showing better outcomes with longer intervention times and fewer female participants. Conclusion: Dog-assisted interventions lasting >15 min seem to be a promising and non-traditional strategy for regulating cortisol levels in children and adolescents in stressful situations. This study outlines gaps in the research and future directions.