PURPOSE A metastatic breast cancer (mBC) diagnosis can affect physical and emotional well-being. However, racial and ethnic differences in receipt of outpatient psychosocial care and supportive care medications in adults with mBC are not well described. METHODS Adults with mBC were identified in the INSIGHT-Clinical Research Network, a database inclusive of >12 million patients receiving care across six New York City health systems. Outpatient psychosocial care was operationalized using Common Procedure Terminology codes for outpatient psychotherapy or counseling. Psychosocial/supportive care medications were defined using Rx Concept Unique Identifier codes. Associations between race/ethnicity and outpatient care and medication use were evaluated using logistic regression. RESULTS Among 5,429 adults in the analytic cohort, mean age was 61 years and <1% were male; 53.6% were non-Hispanic White (NHW), 21.4% non-Hispanic Black (NHB), 15.9% Hispanic, 6.1% Asian/Native Hawaiian/Pacific Islander (A/NH/PI), and 3% other or unknown. Overall, 4.1% had ≥one outpatient psychosocial care visit and 63.4% were prescribed ≥one medication. Adjusted for age, compared with NHW, Hispanic patients were more likely (odds ratio [OR], 2.14 [95% CI, 1.55 to 2.92]) and A/NH/PI patients less likely (OR, 0.35 [95% CI, 0.12 to 0.78]) to have an outpatient visit. NHB (OR, 0.59 [95% CI, 0.51 to 0.68]) and Asian (OR, 0.36 [95% CI, 0.29 to 0.46]) patients were less likely to be prescribed medications. CONCLUSION Despite the prevalence of depression, anxiety, and distress among patients with mBC, we observed low utilization of psychosocial outpatient care. Supportive medication use was more prevalent, although differences observed by race/ethnicity suggest that unmet needs exist.