Outcomes in patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) are poor. Loncastuximab- teserine (Lonca) is an antibody-drug conjugate which was approved by the Food and Drug Administration for the treatment of patients with R/R DLBCL who have received at least two prior lines of therapy, based on the results of the LOTIS-2 trial. However, there are limited data regarding its efficacy in the real-world setting. This retrospective study included 21 US centers and evaluated outcomes of patients with R/R DLBCL treated with Lonca. Our analysis comprises 187 patients with notably higher-risk baseline features compared to those of the LOTIS-2 population, including a higher proportion of patients with bulky disease (17% vs. 0%), high-grade B-cell histology (22% vs. 8%), and increased number of prior lines of therapy (median 4 vs. 3). The complete response rate was 14% and overall response rate was 32%. The median event-free survival and overall survival were 2.1 and 4.6 months, respectively. Those with bulky disease and high-grade B-cell histology had significantly worse outcomes, and those with non-germinal center cell of origin and a complete response to the most recent line of therapy demonstrated superior outcomes. In summary, in this largest retrospective cohort study of Lonca in the real-world setting, the response rates, event-free survival and overall survival were lower than those reported in LOTIS-2, which is likely reflective of its use in higher risk and more heavily pre-treated patients in the real world compared to the patients enrolled on a clinical study.