Abstract Objective: he goal of this work was to perform a systematic review and meta-analysis evaluating and comparing exercise related improvements in various executive function (EF) domains among children and adolescents with attention-deficit hyperactivity disorder (ADHD), Autism Spectrum Disorders (ASD), and Fetal Alcohol Spectrum Disorders (FASD). Methods: A systematic literature research was conducted in PubMed, CENTRAL, and PsycInfo from October 1st, 2018 through January 30th, 2019 for original peer-reviewed articles investigating the relationship between exercise interventions and improvements in three domains of executive function (working memory, attention/set shifting, and response inhibition) among children and adolescents with ADHD, ASD, and FASD. Effect sizes (ES) were extracted and combined with random-effects meta-analytic methods. Covariates and moderators were then analyzed using meta-regression and subgroup analyses. Results: A total of 28 studies met inclusion criteria, containing information on 1,281 youth (N=1197 ADHD, N= 54 ASD, N=30 FASD). For ADHD, exercise interventions were associated with moderate improvements in attention/set-shifting (ES 0.38, 95% CI 0.01-0.75, k=14) and approached significance for working memory (ES 0.35, 95%CI −0.17-0.88, k=5) and response inhibition (ES 0.39, 95%CI −0.02-0.80, k=12). For ASD and FASD, exercise interventions were associated with large improvements in working memory (ES 1.36, 95%CI 1.08-1.64) and response inhibition (ES 0.78, 95%CI 0.21-1.35) and approached significance for attention/set-shifting (ES 0.69, 95% −0.28-1.66). There was evidence of substantial methodologic and substantive heterogeneity among studies. Sample size, mean age, study design, and the number or duration of intervention sessions did not significantly moderate the relationship between exercise and executive function. Conclusion: Exercise interventions among children and adolescents with neurodevelopmental disorders were associated with moderate improvements in executive function domains. Of note, studies of youth with ASD and FASD tended to report higher effect sizes compared to studies of youth with ADHD, albeit few existing studies. Exercise may be a potentially cost-effective and readily implementable intervention to improve executive function in these populations.