In Northern Karnataka, South India, boys' behaviours and attitudes towards girls are regarded as one of the many important proximate structural barriers impeding girls' access to education and academic performance in rural communities. In response to these barriers, public health practitioners developed an intervention, known as the Parivartan program, to confront the wider social and structural influences that shape adolescent boys' perspectives on gender relationships and practices that subjugate adolescent girls. Drawing upon a project ethnography approach, this study presents the findings from two phases of research conducted between 2014 and 2016 among adolescent boys who participated in the Parivartan program. First, 20 baseline qualitative interviews were conducted among male participants (between the ages 14 and 18) enrolled in the program. Next, follow‐up ethnographic research, which included participant observation and ethnographic field note composition, took place one year after commencement of the intervention to illuminate the effects of the program on participants' perspectives. Transcripts and field notes were coded for key themes and emergent categories focused on representing adolescent boys' views and experiences through their narrative accounts. Within the context of an intervention, our findings portray masculinity among participants as simultaneously socially contingent, shifting and still undergoing negotiation, thereby providing an entry point through which program implementers can further encourage boys to transcend patriarchal expectations. Our findings hold important lessons for the design of future HIV and gender‐based interventions with adolescent boys in India.