Background Transcatheter aortic valve replacement (TAVR) has become the standard of care for severe aortic stenosis treatment. Exponential growth in demand has led to prolonged wait times and adverse patient outcomes. Social marginalization may contribute to adverse outcomes. Our objective was to examine the association between different measures of neighborhood‐level marginalization and patient outcomes while on the TAVR waiting list. A secondary objective was to understand if sex modifies this relationship. Methods and Results We conducted a population‐based retrospective cohort study of 11 077 patients in Ontario, Canada, referred to TAVR from April 1, 2018, to March 31, 2022. Primary outcomes were death or hospitalization while on the TAVR wait‐list. Using cause‐specific Cox proportional hazards models, we evaluated the relationship between neighborhood‐level measures of dependency, residential instability, material deprivation, and ethnic and racial concentration with primary outcomes as well as the interaction with sex. After multivariable adjustment, we found a significant relationship between individuals living in the most ethnically and racially concentrated areas (quintile 4 and 5) and mortality (hazard ratio HR, 0.64 95% CI, 0.47–0.88 and HR, 0.73 95% CI, 0.53–1.00, respectively). There was no significant association between material deprivation, dependency, or residential instability with mortality. Women in the highest ethnic or racial concentration quintiles (4 and 5) had significantly lower risks for mortality (HR values of 0.52 and 0.56, respectively) compared with quintile 1. Conclusions Higher neighborhood ethnic or racial concentration was associated with decreased risk for mortality, particular for women on the TAVR waiting list. Further research is needed to understand the drivers of this relationship.