Ectopic breast tissue (EBT) is a well-described entity in the English literature. However, fibroadenoma of the ectopic breast is a rare entity. We present a case of a 13-year-old adolescent girl with a subcutaneous mass in the right axilla that was pathologically identical to fibroadenoma seen in the EBT. To our knowledge, this is the second youngest patient reported with axillary EBT, which should be considered as a part of the differential diagnosis for axillary masses. Keywords : adolescent, axilla, ectopic breast tissue, fibroadenoma, mass Departments of aPediatric Surgery, bPathology, Sami Ulus Maternity and Children’s Hospital and cDepartment of Reproductive Endocrinology, Zubeyde Hanim Women Health Hospital, Ankara, Turkey