Extracanalicular osteomas of the temporal bone are rare, slow-growing, benign neoplasms. Although they may occur anywhere in the temporal bone, they are most common in the mastoid area. Often, symptoms are negligible and treatment is unnecessary. However, surgical removal is indicated when growth of the osteoma causes distressing symptoms or cosmetic issues. The patient described in this report had no symptoms but underwent surgical excision of a mastoid osteoma for cosmetic reasons. At 4-month follow-up, she remains asymptomatic and recurrence-free.