SummaryThis case report describes the presentation, treatment and outcome of an adult German shepherd dog with gastroesophageal intussusception (GEI). The dog’s presenting complaint included acute lethargy, and a single bout of excessive drinking followed by immediate regurgitation. After patient stabilisation, radiographs were taken which revealed a soft tissue opacity in the caudodorsal thorax and lack of a gastric silhouette in the abdomen. The patient was diagnosed with GEI, a laparotomy was performed and the stomach and spleen were surgically reduced. A right-sided incisional gastropexy, left-sided tube gastropexy, splenectomy and narrowing of the oesophageal hiatus were performed. The patient developed aspiration pneumonia postoperatively, likely secondary to megaoesophagus, which responded to antimicrobials. The gastric tube was removed 31 days after surgery and the patient had no further clinical signs eight months postoperatively.