Little research has focused on the ethical issues around using social media for HIV prevention in low- and middle-income countries, such as Peru. This study surveyed participants from the HOPE social media HIV intervention in Peru to assess their experiences and perceptions of ethical issues in the study and the impact of age on their experiences and perceptions. This study found that, compared to younger participants, older participants were more likely to express higher levels of understanding of the consent form (...) and trust that other participants were real. Older participants also reported being less likely to benefit from learning about their HIV status. Findings suggest that age plays a role in participants’ experiences in a social-media-based HIV intervention. (shrink)