There is a paucity of validated mental health measures for assessing psychological well-being among HIV-affected youth. We sought to explore the psychometric properties and validity of the Achenbach Youth Self-Report and Child Posttraumatic Stress Disorder Symptom Scale among orphans and vulnerable children (OVC) living in Lusaka, Zambia. These scales were administered to 210 OVC aged 13 to 17 years via audio computer-assisted self-interview. Confirmatory factor analysis was used to assess scale structure, Cronbach’s alpha for internal consistency, and correlations between scales related to mental or psychosocial health for construct validity. A known-groups validation was conducted using local identifications of youth with and without significant psychosocial problems, and test–retest reliability was assessed. Scales exhibited good internal reliability (α > .80), adequate criterion validity (area under the curve > .70), and moderate test–retest reliability (.62-.68). Findings support the utility of these symptom scales for identifying OVC experiencing significant psychosocial problems in Zambia.