HIV/AIDS is taking a heavy toll on South African youth. Reducing their risk for HIV requires an understanding of the determinants of their HIV risk behaviours that are amendable to intervention-induced change. This study draws upon the theory of planned behaviour to identify the modifiable determinants of the intention to use condoms among Xhosa-speaking South African adolescents. The participants were 390 Xhosa-speaking 6th grade students (mean age = 12.1 years) in public schools in the township of Mdantsane, South Africa who completed an anonymous questionnaire. Multiple regression revealed that attitude and perceived behavioural control were significantly related to the intention to use condoms, whereas subjective norm was not, controlling for sexual experience, gender, and language preference. Consistent with this were additional analyses using beliefs as predictors: Hedonistic behavioural beliefs and control beliefs about condom-use negotiation and technical skills predicted intention, whereas normative beliefs did not. The theory of planned behaviour may be a useful model of condom use among Xhosa-speaking South African adolescents. An emphasis on beliefs about the adverse effects of condom use on sexual enjoyment, the ability to negotiate condom use, and the ability to use condoms correctly might improve the efficacy of HIV/STD interventions for such adolescents.