BACKGROUND: Coronary artery calcium (CAC) scoring predicts cardiovascular risk, but social determinants of health may play a role in its prognostic ability. We examined whether the Social Vulnerability Index (SVI) modifies the association between CAC and major adverse cardiovascular events (MACE) in a community-based screening cohort. METHODS: We studied 49 224 participants without known cardiovascular disease referred for CAC scanning from 2014 to 2022 based on cardiovascular risk factors. SVI was determined for each participant based on the census tract. We examined 8-year incidence of MACE (myocardial infarction, stroke, heart failure, revascularization, death) by SVI quartile across CAC score strata (0, 1-99, 100-399, ≥400). Cox proportional hazard models estimated hazard ratios for MACE, associated with demographics, metabolic factors, and CAC. RESULTS: Higher SVI was associated with female sex, non-White race, greater comorbidities, and higher CAC scores. The 8-year MACE rate increased monotonically by SVI quartile, with a hazard ratio of 1.54 (95% CI, 1.24-1.90, CONCLUSIONS: In this no-cost community-based CAC cohort, SVI independently predicted adverse cardiovascular outcomes across all CAC strata. Focused efforts to mitigate the incremental risk associated with social vulnerability are needed.