This study identifies traditional conceptions of homosexuality and social stereotypes about gay men among Brazilian teenagers. A total of 178 adolescents (50% girls; age range 11–16 years) participated in 45 focus groups held at five schools in Brazil, in which a semi-structured script and videos depicting homophobic bullying were used to elicit their opinions. Thematic analysis revealed a dichotomy in their conceptions and stereotypes: While some spontaneously expressed homophobic conceptions (e.g., homosexuality is a sin or a pathology) supported by stereotypes (e.g., gays are not real men or sexually harass heterosexuals), others openly condemned homophobia and actively voiced their objections to the former group’s homophobic views. The analysis also reveals the persisting influence of religious beliefs in their perceptions. The study highlights the need to foster critical reflections in educational settings and the formulation of strategies to deconstruct homophobia and promote diversity and inclusion.