OBJECTIVES:To investigate whether the presence of persistent self-reported oral lesions (PSOLs) is associated with sexual behaviors and with the presence of sexually transmitted infections (STIs) in individuals aged 16-25 years in the state capitals of Brazil. MATERIALS AND METHODS:Data from the POP-Brazil study were analyzed. An association analysis was performed by Poisson regression with the presence of PSOLs as the outcome. The exposure variables were the age at first sexual intercourse, the number of partners, oral sex practice, and aspects of condom use for model 1, and the presence of a self-reported STI or a positive rapid test for HIV/syphilis and the presence of genital human papillomavirus (HPV) for model 2. The results were adjusted for socioeconomic variables. RESULTS:The prevalence of PSOLs was 76% higher among individuals who had two or more sexual partners in the past year (p = 0.046) and 68% higher in those who reported not using condoms for contraception (p = 0.032). The group with HIV/syphilis or self-reported STI had a 140% higher PSOL prevalence (p = 0.003). CONCLUSIONS:The self-report of oral lesions in adolescents and young adults may suggest risky sexual behavior and the presence of STI. CLINICAL RELEVANCE:It is necessary to contextualize the reality of the young person to optimize oral health care.