Diseases of the gallbladder commonly manifest as cholelithiasis and gallbladder cancer. Cholelithiasis has become a significant health problem in developed societies, affecting 10-15% of the adult population. Gallbladder polyps are incidentally detected in approximately 4-7% of patients. In addition, other gallbladder problems may also occur, but these are extremely rare: remnant cystic duct, gallbladder anomalies, Mirizzi syndrome, and gallbladder parasites. Endoscopic ultrasound (EUS) is an excellent method for visualizing the bile duct and gallbladder given its proximity when imaging from the duodenum. EUS can be used for evaluation of gallbladder disease that includes investigation of suspected cholelithiasis or biliary sludge, imaging of polypoid lesions of the gallbladder, and diagnosis and staging of gallbladder cancer. This procedure can be helpful to further distinguish benign from malignant or potentially malignant gallbladder polyps and play an important role in determining the treatment strategy for gallbladder polyps. Furthermore, EUS can help in the diagnosis of rarely gallbladder diseases such as remnant cystic duct, gallbladder anomalies, Mirizzi syndrome, and gallbladder parasites. Recent studies have suggested that EUS-guided gallbladder drainage (EUS-GBD) can be considered to be an effective emergency treatment for acute cholecystitis patients at high risk for surgery.