Evaluation of HER2 status and programmed death-ligand 1 (PD-L1) combined positive score (CPS) is mandatory in all patients with HER2-positive metastatic adenocarcinoma of the gastroesophageal junction (GEJ) not only to tailor first-line therapy but also to improve individual survival outcome. However, despite advances in the therapeutic management of metastatic adenocarcinoma of the GEJ, prognosis of these patients remains poor. We report a patient with HER2-positive metastatic adenocarcinoma of the GEJ who showed significant clinical and radiological benefit to HER2-directed therapy in the fifth-line therapeutic setting.