Introduction: Endoscopic stenting for malignant gastroduodenal outlet obstruction (MGOO) is described as ineffective and not long-lasting despite a few favorable studies. This study aimed to evaluate the clinical outcomes of a large series of patients in a tertiary center. Methods: A single-center retrospective study was performed using data collected from all patients who received palliative duodenal self-expandable metal stents between January 2011 and December 2016. The primary endpoints were patient diet after the first duodenal procedure (Gastric Outlet Obstruction Scoring System, GOOSS) and clinical success. The secondary endpoints were the median patency duration (calculated according to the Kaplan-Meier method) and the cumulative incidence of reintervention. Results: Two-hundred twenty patients were included. The increase in the GOOSS score was significant (p < 0.001), and the clinical success rate was 86.3%. The median estimated patency duration was 9.0 months [6.5-29.1]. Patients with pancreatic adenocarcinoma had significantly longer patency durations (p = 0.02). The estimated cumulative probability of a second duodenal procedure after 4 months was 13%. Conclusions: In this large series of patients who underwent duodenal stenting for MGOO, we observed significant changes in GOOSS scores, a relatively long patency duration compared to findings in previous series, and a low probability of subsequent duodenal procedures, primarily due to a low median overall survival time (4 months).