Objective: To verify the association between social determinants of health and the vulnerability of adolescents to Sexually Transmitted Infections (STIs). Method: Cross-sectional study, performed with 287 students aged 11 to 17 years, in the outskirts of Fortaleza, Ceará, Brazil, from August do September 2016. Two instruments were used, one destined to social determinants of health and another to investigating the vulnerability to STIs. The magnitude of associations was expressed through odds ratio and interval of confidence, considering a 5% significance level. This research was approved by the Research Ethics Committee of the Federal University of Ceará. Results: 212 (73.9%) adolescents were considered more vulnerable, with a score ≥ 4. The intermediate social determinant “housing (home ownership)” obtained significant association with with the vulnerability to STIs (p of 0.022; CI 1.1 to 3.3; OR 1.9). Conclusion: The intermediate social determinant “type of housing” influences the vulnerability to STAs.