Gallbladder wall thickening is defined as a wall measurement greater than 3 mm on ultrasound, measured in the non-contracted gallbladder. In the appropriate clinical setting, wall thickening combined with gallstones and a positive sonographic Murphy sign supports the diagnosis of acute cholecystitis. However, wall thickening is a nonspecific finding also seen in hypoalbuminemia, ascites, heart failure, hepatitis, and adenomyomatosis. Sonographers must correlate the finding with the patient’s clinical presentation.