Purpose: The objective was to examine potential socioeconomic inequities in guideline recommended quality of care as well as several clinical outcomes among first-time inpatients with major depressive disorder (MDD) in a tax-financed universal health care system. Patients and Methods: A nationwide cohort study was performed based on individual-level record linkage of public registers in Denmark. The study included all adult incident inpatients with MDD at Danish psychiatric hospitals in the period 2011–2017 (n=10,949). Socioeconomic position was assessed according to the level of education and income. Outcomes included quality of depression care for inpatients as reflected by the fulfillment of guideline recommended quality of care measures as well as clinical outcomes in terms of all-cause mortality, suicidal behavior, readmission for depression and all-cause readmission. Results: Patients with low-level education or low-level income were statistically significantly less likely to receive high quality of in-hospital care, defined as fulfillment of at least 70% of relevant performance measures (adjusted relative risk (RR) 0.92 and 0.87, respectively). In addition, the same patients had a higher all-cause mortality (adjusted RR 1.22 and 1.41, respectively). Patients with low education or middle income were associated with a higher risk of suicidal behavior (adjusted RR 1.28 and 1.19, respectively). While no differences were found in the risk of all-cause readmission, low-level education and income was associated with a lower risk of readmission due to MDD (adjusted RR 0.91 and 0.87, respectively). Conclusion: Inequities in quality of care and clinical outcomes were observed among MDD inpatients in a tax-financed universal health care system, indicating that lack of access to care and insurance is not the only explanation for inequity in health.