Sigmoid volvulus is a rare but life-threatening diagnosis in the paediatric population and has only been reported a handful of times in the literature. We describe the case of a 14-year-old boy with abdominal pain and diarrhoea who was diagnosed with a sigmoid volvulus after initially being managed for infectious gastroenteritis. The patient initially presented with a 5-day history of watery stool, 1-day history of profuse vomiting and colicky abdominal pain. Whilst admitted, the patient developed worsening abdominal pain, distention and hyperresonance to percussion. Computed tomography demonstrated a dilated sigmoid colon, with a mesenteric ‘whirl sign’ around the inferior mesenteric artery. The patient underwent a laparotomy, which confirmed a sigmoid volvulus, requiring an anterior resection. This case emphasises the importance for general surgeons to consider the rare diagnosis of sigmoid volvulus in children.