Kawasaki syndrome (KS) is a self-limiting childhood disease. Gallbladder hydrops is an uncommon manifestation of this syndrome, found rarely in infants. We report the case of a 7-month-old girl with KS manifesting as gallbladder hydrops, which resolved spontaneously during follow-up. To our knowledge, this represents the youngest such case ever reported. We discuss the clinical characteristics, radiological features, and outcome of gallbladder hydrops in KS during infancy to help understand this rare complication.