Abstract Black patients with tetralogy of Fallot (TOF) have higher mortality than White patients. Health disparities related to other patient-important outcomes, such as exercise performance, have not been studied in this population. We aimed to determine if there are racial disparities related to exercise performance in patients with TOF and to investigate possible mediators of those disparities. We conducted a retrospective single center study of patients aged 8–25 years with repaired TOF who completed maximal cardiorespiratory exercise tests between 2007 and 2020. The primary outcome was percent predicted oxygen consumption at peak exercise. We used linear regression to determine if race was associated with exercise performance. We used mediation analysis to investigate insurance coverage and neighborhood Child Opportunity Index as possible mediators of this relationship. The study cohort included 163 patients with TOF (136 non-Hispanic/Latinx White and 27 non-Hispanic/Latinx Black). In multivariable analysis, Black patients had a lower percent predicted peak oxygen consumption than White patients by 6.71 percentage points (95% CI − 12.71, − 0.70; p = 0.029). Mediation analysis revealed that the indirect effect of race through insurance coverage accounted for 34.1% of the decrease in exercise performance. Child Opportunity Index was not a statistically significant mediator. Black patients with TOF had worse exercise performance than White patients. Differences in insurance coverage accounted for a significant portion of this difference. Exercise performance is an important outcome for patients with TOF, and further investigation is needed to better understand this disparity and develop interventions to address it.