Objective To identify the determinants of the intention to use and actual use of condoms in a sample of French adolescents based on Ajzen's Theory of Planned Behaviour. Method Two-hundred-and-thirty French secondary-school students (mean age: 17.68 years; SD = 1.08) completed a questionnaire about condom use intention. Results ‘Perceived behavioural control’, ‘individual attitudes’, ‘subjective socio-cultural norms’ and ‘subjective norms of close friends and relatives’ are the main factors explaining 33% of variance of condom use intention. For girls, intention is essentially associated with perceived control, subjective norms (‘close friends and relatives’, and then, ‘socio-cultural norms’) and individual attitudes, whereas for boys, it is more closely linked to individual attitudes and to subjective socio-cultural norms. The best predictors of the intention to use a condom are perceived control and individual attitudes for girls while, for boys, individual attitudes come before perceived control. Conclusion In order to design effective programmes for prevention of sexually transmitted infections, the determinants of the intention to use condoms must be considered.