Suntonpiyapan A.Sarnkhaowkhom C.Santre S.Mahidol University2026-06-212026-06-212026-01-01International Journal of Women S Health Vol.18 (2026)https://repository.li.mahidol.ac.th/handle/123456789/117449Background: Dual contraception, the concurrent use of condoms and another effective method, is recommended for adolescents to prevent sexually transmitted infections (STIs) and unintended pregnancy. Identifying determinants of adolescent females’ intention to use dual contraception is essential for promoting sexual and reproductive health. This study integrates the Health Belief Model and the Theory of Planned Behavior and to examine influencing factors. Objective: To identify determinants of intention to use dual contraception among female upper secondary school students in Thailand. Methods: A cross-sectional study was conducted among 407 female upper secondary school students in Nonthaburi Province, Thailand. Data were collected using a researcher-developed questionnaire between November 2025 and January 2026. Statistical analyses included descriptive statistics, Chi-square tests, Pearson’s correlation coefficients, and multiple regression analysis. Statistical significance was set at p < 0.05. Results: Overall intention to use dual contraception was high (M = 4.17, SD = 0.78). Eleven variables were significantly associated with intention (p < 0.05), including Grade Point Average, knowledge of dual contraception, personal life goals, subjective norms, perceived behavioral control, attitudes, perceived susceptibility, perceived severity of unintended pregnancy and STIs, perceived benefits, perceived barriers, and self-efficacy. Five factors significantly predicted intention, in descending order of predictive power: self-efficacy in dual contraception use (β = 0.395, t = 9.105, p = 0.000) perceived barriers to use dual contraception (β = −0.183, t = −4.743, p = 0.000); perceived severity of unintended pregnancy and STIs (β = 0.180, t = 3.497, p = 0.000); perceived susceptibility to risks of non-use (β = 0.121, t = 2.810, p = 0.005); and perceived behavioral control (β = 0.100, t = 2.234, p = 0.026). These variables jointly explained 61.60% of the variance in intention (Adjusted R² = 0.616, p < 0.05). Conclusion: Intention to use dual contraception among female students was high and was significantly associated with personal, cognitive, and psychosocial factors derived from the integrated theoretical framework. The findings can inform the development of targeted interventions, adolescent-friendly services, and collaborative strategies to enhance informed decision-making and promote dual-method contraceptive use among adolescents.NursingMedicineArticleSCOPUS10.2147/IJWH.S6053702-s2.0-10504180827511791411