Enteric duplication is rare in dogs. Here, we report the rarest form of duplication in which two segments are parallel and share a wall for most of their lengths. A nine-year-old spayed female Yorkshire terrier was referred to the Veterinary Medical Teaching Hospital at Gyeongsang National University due to anorexia and diarrhoea. Physical examination, haematological examination, radiography, and ultrasonography were performed. On physical examination, dry, pale mucous membrane was identified. Moderate anaemia with decreased packed cell volume was detected in complete blood count. Serum urea nitrogen and creatinine levels were mildly increased. Radiographic images revealed no significant findings. On ultrasonographic examination, a multi-layered appearance of a focal small intestinal segment was identified in the left mid abdomen. Following the lesion, it was divided into two small intestinal segments. Based on imaging findings, intussusceptions or enteric duplication were suspected. To resect the abnormal small intestinal segment, enterectomy was performed. Follow-up was not performed because the patient expired during the postoperative recovery time. The histopathological diagnosis was non-communicating small intestinal duplication. Non-communicating intestinal duplication is related to embryologic abnormalities and is usually concurrent with other anomalies such as vertebral malformations and urogenital duplications. However, this case had no other anomalies associated with the malformation of the intestine.