Streptococcus oralis (S. oralis) belongs to the viridans group Streptococci (VGS) and is part of the normal flora of the human oral cavity, oropharynx, and nasopharynx. S. oralis meningitis is very rare and there are no reports of ventriculo-peritoneal shunt (VPS) infection caused by this bacterium. With this case report we aimed to describe the characteristics of such an extremely rare case and explore its clinical significance. A 10-year-old girl, with a history of metastatic cerebellar medulloblastoma treated with surgical resection followed by chemotherapy, radiotherapy and a VPS, presented with abdominal pain and a peri‑appendicular collection. As the pain worsened while on co-amoxiclav, she underwent laparoscopic exploration, drainage of purulent peritoneal fluid, externalization of her VPS, followed by appendicectomy. A diagnosis of appendicitis was excluded by the normal macroscopic and histological examination of the appendix, and a negative fluid culture result. Cerebrospinal fluid from the externalized VPS 9 days after shunt externalization grew S. oralis. She was treated with antibiotics, extended drainage with a ventricular drain and eventually rendered shunt-free. Our case illustrates an extremely rare infection secondary to the small scalp defect. Predisposing factors in our case included an externally-facing suture knot, the use of an adult valve in a small child, and previous radiotherapy. To the best of our knowledge this is the first case of VPS infection due to S. oralis reported worldwide so far. Neurosurgeons should be aware of the rare VPS infection causes and their predisposing factors, particularly the surgery-related and avoidable ones. Simple surgical maneuvers and choice of implantable shunt component can remarkably reduce morbidity in vulnerable pediatric patients.