Short, reliable, easily administered executive function (EF) assessment tools are needed to measure EF in low- and middle-income countries, particularly in sub-Saharan Africa given the prevalence of human immunodeficiency virus (HIV)-associated neurocognitive disorder. We administered Oxford Cognitive Screen-Executive Function (OCS-EF) to 932 rural South African females (mean age 19.7 years). OCS-EF includes seven tasks: two hot inhibition tasks (a modified Iowa Gambling Task, emotional go/no-go) and five cool EF tasks, two switching tasks (visuospatial rule-finding, geometric trails) and three working memory tasks (digit recall, selection and figure drawing). We performed confirmatory factor analysis testing whether a three-factor, two-factor hot-cool, two-factor working memory and inhibition/switching, or one-factor EF model fitted the data better. The three-factor (switching, inhibition and working memory) model had the best local and global fit (chi(2) (11) 24.21, p = 0.012; RMSEA 0.036; CFI 0.920; CD 0.617). We demonstrated the feasibility of OCS-EF administration by trained laypeople, the tripartite structure of EF amongst adolescent females and the factorial validity of OCS-EF in this population and context. OCS-EF tablet-based cognitive assessment tool can be administered by trained laypeople and is a valid tool for assessing cognition at scale amongst adolescents in rural South Africa and similar environments.