Background <p>Male breast cancer (MBC) is a rare malignancy, and research on its prognostic factors remains limited. Marital status has been identified as a prognostic determinant in various cancers; however<b>,</b> the impact of marital status on MBC survival outcomes remains understudied<b>.</b> This study examines the relationship between marital status and survival in MBC patients using a large, population-based cohort.</p> Methods <p>A retrospective cohort study was conducted using the Surveillance, Epidemiology, and End Results (SEER) 17 Registries database (2010–2021). MBC patients (<i>n</i> = 5,994) were categorized into four marital status groups: married, unmarried, divorced, and widowed<b>.</b> Kaplan–Meier survival curves, log-rank tests, and Cox proportional hazards models were used to assess overall survival (OS) and disease-specific survival (DSS).</p> Results <p>Significant differences in OS and DSS were observed among marital status groups (<i>p</i> &lt; 0.001). Widowed patients had the poorest survival outcomes, with a 2.59 times higher increased mortality risk (HR = 2.594, 95% CI: 2.246–2.996, <i>p</i> &lt; 0.001) compared to married individuals in univariate analysis. This association remained significant in multivariate analysis, with widowed patients demonstrating a 1.72 times higher mortality risk (HR = 1.724, 95% CI: 1.421–2.092, <i>p</i> &lt; 0.001) after adjustment for clinicopathological and demographic variables. Unmarried and divorced patients also had poorer survival outcomes than married patients, albeit with lower hazard ratios.</p> Conclusions <p>Marital status is an independent prognostic factor in MBC, with widowed patients experiencing the poorest outcomes. These findings underscore the important role of social and psychological support in cancer prognosis. Integrating psychosocial support programs and patient-centered care approaches into oncological practice can help reduce survival disparities<b>.</b></p>