Background: Athletes with intellectual disability represent a unique population who experiences the contrasting effects of cognitive deficits and benefits of sports on balance. This study investigated the combined impact of intellectual disability and sport practice on balance. Method: Center-of-pressure excursion in bipedal stance of 2 disability (with and without intellectual disability) × 2 sport practice (athlete and novice) participant groups was measured in several balance conditions. Results: Sport practice exerted no significant effect on any of the center-of-pressure measures used. In contrast, intellectual disability's effects on balance, which were most apparent in challenging balance conditions, were significant (p < 0.05) and had large effect sizes ([partial eta-squared] > 0.13). Conclusion: The negative effects of cognitive deficits on the balance of young adults with intellectual disability underscore the need for effective interventions. Although findings did not support sports' balance-remediating potential, the value of sport participation for individuals with intellectual disability cannot be fully dismissed just yet.