Tinnitus is commonly referred to as “ringing in the ears.” Epidemiologic studies highlight challenges associated with clinical determination of tinnitus and ascertainment of its etiology, functional effects, temporal characteristics, psychoacoustic parameters, and risk factors. Because no standards exist for capturing these factors as measures, direct comparison of data between studies is not possible. This report suggests terminology and definitions to promote standardization, with a brief overview of findings from selected population-based epidemiologic studies. Tinnitus-specific data are presented from the Noise Outcomes in Servicemembers Epidemiology study. Further epidemiologic studies are needed to develop tinnitus treatment and a cure for this chronic condition.