Abstract: The Veterans Health Administration (VHA) has committed to increasing health equity for all veterans, which is needed to address disparities in health care and outcomes experienced by Black VHA patients. In this cross-sectional retrospective observational study, we analyzed VHA operations data on all patients receiving mental health treatment at VHA in fiscal year 2021 (N = 1,602,865). Facility-level negative binomial regressions demonstrated that Black patients were disproportionately treated at large, complex, urban facilities in the Southern United States that had higher overall volumes of mental health care and staff but lower mental health staffing ratios and less care for each patient. Though they utilized facilities with lower visits and hours per patient, Black versus non-Black patients had on average more visits and hours per patient. Accounting for these gaps using patient-level Kitagawa-Oaxaca-Blinder (KOB) decomposition analyses, we found (a) negligible and small within-facility effects, (b) between-facility effects that demonstrated that Black patients would have received more treatment than non-Black patients had they utilized facilities in the same proportions as non-Black patients, and (c) excluded variables in unadjusted KOB and excluded variables and covariates (e.g., age, homeless treatment receipt) in adjusted KOB most strongly accounted for gaps. Combining facility-level analyses with novel use of patient-level KOB revealed nuance in the potential inequities experienced by Black VHA mental health patients while demonstrating the need for additional research to examine whether Black patients receive the proper treatments for their mental health conditions and at the optimum dose.