Accessory splenic torsion is a rare condition that occurs when the accessory spleen twist on its pedicle, leading to a loss of blood supply and subsequent tissue damage. It is a rare cause of acute abdomen with few cases reported in the literature. We report a case of accessory spleen torsion in a 16-year-old male with abdominal pain. The patient, whose lesion was interpreted as a hematoma on imaging at an external center, was admitted to our center with increased, intermittent abdominal pain. The patient's complaints and physical examination were similar to peptic ulcer perforation. Abdominal ultrasonography and abdominal CT performed for differential diagnosis showed a 45x50 mm heterogeneous, hypodense, well-defined lesion located in the splenic hilus, posterior to the stomach, and adjacent to the pancreatic tail. In our center, the lesion was considered to be lesser sac omental torsion and was operated on. A 720-degree torsed accessory spleen was found at surgery and resected. Accessory splenic torsion is not primarily a condition that comes to mind in children with abdominal pain. However, in case of delay in diagnosis and treatment, many complications can be seen. The fact that ultrasonography or computed tomography cannot clearly define accessory splenic torsion also complicates this diagnosis. In such cases, performing diagnostic laparotomy/laparoscopy reveals the definitive diagnosis and is very important in preventing complications.