Purpose <p>Lymphedema is a chronic and progressive condition that significantly affects functional outcomes and quality of life. Social determinants of health (SDOH) contribute substantially to health disparities; however, their association with lymphedema severity and treatment adherence remains underexplored. This study aimed to evaluate the association between SDOH and both lymphedema severity and adherence to therapy.</p> Methods <p>A retrospective chart review was conducted on 300 patients diagnosed with lymphedema (ICD-10: I89.0) who received care at the Georgia Cancer Center between March 2019 and December 2023. SDOH variables were categorized across five domains: economic stability, education, healthcare access, neighborhood environment, and social/community context. Lymphedema severity was assessed using the International Society of Lymphology staging system and dichotomized as moderate or less versus severe. Treatment adherence was measured as a composite score (0–100%) based on four components of complete decongestive therapy and categorized as low (&lt; 50%) or high (≥ 50%). Multivariable logistic regression was used to examine associations.</p> Results <p>Among 295 eligible patients included in the final analysis, transportation access, ethnicity, and gender were significantly associated with both lymphedema severity and treatment adherence (<i>p</i> &lt; 0.05). Limited transportation access and lower socioeconomic indicators were associated with higher odds of severe lymphedema and lower adherence. African American ethnicity and male gender were also associated with worse outcomes.</p> Conclusions <p>SDOH significantly influences lymphedema severity and treatment adherence. Addressing barriers such as transportation and socioeconomic disparities is critical to improving outcomes and reducing inequities in lymphedema care.</p>