Purpose <p>Structural racism may be associated with disparities in breast cancer access to care and outcomes. We examined the association between contemporary mortgage lending bias (redlining) and the receipt of guideline-concordant systemic treatment.</p> Methods <p>Women with stage I–III invasive breast cancer in 2010–2017 were identified from the Surveillance, Epidemiology, and End Results-Medicare linked database. Contemporary redlining was estimated using 2010–2017 Home Mortgage Disclosure Act data. Simple and multiple logistic regression models estimated the unadjusted and adjusted odds of receiving guideline-concordant systemic treatment: appropriate receipt of chemotherapy, HER2/neu (HER2)-targeted therapy, hormonal therapy, and a composite systemic treatment measure.</p> Results <p>Overall compliance rates were 85%, 96%, and 87% for chemotherapy, HER2-targeted therapy, and hormonal therapy, respectively. For the composite outcome, 95% received some or fully concordant care. In unadjusted and adjusted models, women living in higher redlined neighborhoods were less likely to receive guideline-concordant care for all modalities, except hormonal therapy (<i>p</i> = 0.846). For HER2-targeted therapy and composite score, the redlining effect differed by dual Medicare-Medicaid enrollment eligibility status. Dual eligibility eliminated the negative effect of redlining. Among those not dual eligible, the negative effect of redlining persisted.</p> Conclusions <p>Older breast cancer survivors living in higher redlined areas were less likely to receive guideline-concordant chemotherapy, HER2-targeted therapy, and overall systemic treatment. While more work is needed to better understand structural racism and neighborhood socioeconomic disinvestment to address equitable access to cancer care, the housing sector may be one actionable policy target. Care teams should consider patient context to ensure high quality care.</p>