The ectopic thyroid tissue is the result of abnormality in embryological development and migration. Ectopic thyroid tissue located in or adjacent to the gallbladder wall is extremely rare with only two cases reported since 1969. These cases were all identified incidentally by pathological examination after cholecystectomy for acute or chronic cholecystitis. We here report a case of ectopic thyroid tissue presenting as a gallbladder mass in a 60-year-old woman who underwent cholecystectomy. Ectopic thyroid tissue in the gallbladder wall was confirmed by histopathology.