Background: Community-level factors contribute to living donor kidney transplantation disparities but may also influence the interventions aimed to mitigate these disparities. The Living Donor Navigator Program was designed to separate the advocacy role from the patient in need of transplantation—friends/family are encouraged to participate as the patients’ advocates to identify living donors, though some of the patients participate alone as self-advocates. Self-advocates have a lower living donor kidney transplantation likelihood compared to the patients with an advocate. We sought to evaluate the relationship between the patients’ community-level vulnerability and living donor navigator self-advocacy as a surrogate for program fidelity. Methods: This single-center, retrospective study included 110 Living Donor Navigator participants (April 2017–June 2019). Program fidelity was assessed using the participants’ advocacy status. Measures of community vulnerability were obtained from the Centers for Disease Control and Prevention Social Vulnerability Index. Modified Poisson regression was used to evaluate the association between community-level vulnerability and living donor navigator self-advocacy. Results: Of the 110 participants, 19% (n = 21) were self-advocates. For every 10% increase in community-level vulnerability, patients had 17% higher risk of self-advocacy (adjusted relative risk 1.17, 95% confidence interval: 1.03–1.32, P = .01). Living in areas with greater unemployment (adjusted relative risk: 1.18, 95% confidence interval: 1.04–1.33, P = .01), single-parent households (adjusted relative risk: 1.23, 95% confidence interval: 1.06–1.42, P = .006), minority population (adjusted relative risk: 1.30, 95% confidence interval: 1.04–1.55, P = .02), or no-vehicle households (adjusted relative risk: 1.17, 95% confidence interval: 1.02–1.35, P = .02) were associated with increased risk of self-advocacy. Conclusion: Having a greater community-level vulnerability was associated with poor Living Donor Navigator Program fidelity. The potential barriers identified using the Social Vulnerability Index may direct resource allocation and program refinement to optimize program fidelity and efficacy for all participants.