Aims: This article reports on the development and psychometric properties of an instrument to evaluate school-based HIV/ AIDS interventions aimed at adolescents in three African sites. Methods: The instrument was developed in a series of steps that involved a review of existing instruments; use of empirical data and secondary literature supporting an association between the variables of interest and sexual intercourse or condom use; operationalizing the constructs of the theoretical model employed; and using the objectives of the intervention. Test-retest reliability studies were conducted at each site.