Acute acalculous cholecystitis is inflammation of the gallbladder in the absence of gallstones. It usually occurs in critically ill patients and is rare in the pediatric age group. We describe a 12-year-old boy who presented with fever, jaundice, and abdominal pain and was found to have acute acalculous cholecystitis, sacroiliitis, and pelvic osteomyelitis associated with bacteremia as a result of Staphylococcus aureus. Antibiotic therapy without surgical intervention was effective. A high index of suspicion is required to make an early diagnosis and institute appropriate treatment for children with this condition. Although cholecystectomy has been considered the standard therapy, medical treatment alone can be successful.