Background: Traditional forms of masculinity strongly influence men's and women's wellbeing. Objective: This study has two aims: (i) to explore notions of various forms of masculinities in young Nicaraguan men participating in programs addressing sexual health, reproductive health, and/or gender equality and (ii) to find out how these young men perceive their involvement in actions aimed at reducing violence against women (VAW). Design: A qualitative grounded theory study. Data were collected through six focus groups and two in-depth interviews with altogether 62 young men. Results: Our analysis showed that the informants experienced a process of change, labeled ‘Expanding your mind’, in which we identified four interrelated subcategories: The apprentice, The responsible/respectful man, The proactive peer educator, and ‘The feminist man’. The process showed how an increased awareness of gender inequities facilitated the emergence of values (respect and responsibility) and behavior (thoughtful action) that contributed to increase the informant's critical thinking and agency at individual, social, and political levels. The process was influenced by individual and external factors. Conclusions: Multiple progressive masculinities can emerge from programs challenging patriarchy in this Latin American setting. The masculinities identified in this study show a range of attitudes and behaviors; however, all lean toward more equitable gender relations. The results suggest that learning about sexual and reproductive health does not directly imply developing more gender-equitable attitudes and behaviors or a greater willingness to prevent VAW. It is paramount that interventions to challenge machismo in this setting continue and are expanded to reach more young men.