Background: Positive adolescent sexual health is supported by effective school-based sex education. Methods to promote positive sexual health need to reflect determinants of contraception intention, which must include understanding gender and age (year group) differences. To date, there has been limited theory-based exploration of these determinants in school age participants, placing limitations on sexual health educators to tailor learning most effectively. Methods: Cross-sectional survey data were collected from UK school pupils (n=1378) aged 12-16 years. Measures included theory of planned behaviour, prototype willingness, anticipated regret and knowledge items. Linear regression determined significant predictors of intention to use condoms, the oral contraceptive pill and emergency contraception (EC). The significance of differences by gender and school year was evaluated using t-tests and analysis of variance (ANOVA). Results: Three distinct predictive models emerged for condom, pill and EC use, predicting 36%, 18% and 23% of variance respectively. Attitude, gender and anticipated regret for unprotected sex significantly predicted intention for all types of contraception (P<0.001). The effects of other explanatory variables differed by contraceptive. Girls scored higher on all variables except condom intention, and intention scores peaked in Year 10. Conclusion: Intention to use condoms, the pill and EC have different predictive profiles, with girls more strongly motivated and Year 10 a crucial stage for intention. Social comparisons and control beliefs exert different effects across contraceptive types, whereas attitudes and anticipated regret are consistently strong influences. The findings suggest clear scope for supporting sexual health and well being through modified school sex education.