The giant diverticulum of the sigmoid colon is a rare clinical condition characterized by a high risk of complications. Its etiology is multifactorial, with longstanding diverticular disease and motor dysfunction of the colon as risk factors. Even though its diagnosis could be challenging, clinicians can rely on barium enemas revealing the characteristic findings of a large, air-filled sac adjacent to the colon on a computed tomography scan and colonoscopy. The use of these tools aids in ruling out alternative diagnoses and confirming the presence of a diverticulum. Timely surgical management is essential, also in asymptomatic fit-for-surgery patients, to prevent potential complications.