There is a well-documented epidemiological association between auditory hallucinations and self-harm in the general population. However, there has been limited research examining specific characteristics of auditory hallucinations (e.g., type, source, or context of voices) as correlates of self-harm. We used prospective data from the Tokyo Teen Cohort to explore whether characteristics of voices reported at age 14 were differentially associated with self-harm behaviors at ages 14 and 16. Among respondents with auditory hallucinations, respondents who experienced voices that "said something bad" about them or commented on their thoughts and actions were most likely to report concurrent self-harm, whereas positive or praising voices were protective. Negative voices continued to predict self-harm two years later, at age 16, even with adjustment for self-harm at age 14. The age of the voices, source of the voices, and context (e.g., falling asleep or while sick) was not associated with likelihood of reporting concurrent or subsequent self-harm behaviors. Assessing for negative voices in particular, rather than auditory hallucinations or psychotic experiences more broadly, may provide a more specific indicator of risk for self-harm among adolescents. The real-world utility of these epidemiological findings should be further examined in clinical settings.