Adolescents from urban communities are at risk for unhealthy snacking behaviors. Youth advocacy interventions are shown to improve certain adolescent health behaviors, such as substance use. However, it remains unclear if youth advocacy is a feasible method to promote healthy snacking. As such, the aim of this study was to examine the feasibility of a youth advocacy program promoting healthy snacking among adolescents in New York City by conducting a mixed-methods process evaluation. Adolescents (12-18 years) at a Boys and Girls Club in New York City were recruited to participate in a 12-session adaptation of the Youth Engagement and Action for Health! program to advocate for the promotion of healthy snacks in corner stores. A mixed-methods process evaluation was conducted to assess recruitment, reach (attendance), dose delivered (amount of intervention delivered), fidelity (degree to which intervention was implemented according to curriculum) and dose received (participant engagement/satisfaction). Satisfaction was also evaluated through focus groups. Descriptive statistics were calculated for quantitative data, and focus groups were analyzed using thematic analysis. Participant retention (94.74%), attendance (93.52%), dose delivered (98.94%), fidelity (98.5%), engagement (4.97/5) and program satisfaction (4/5) were high. Focus groups (n = 6; 28 participants) revealed that participants learned about nutrition, enjoyed being advocates and improved snacking behaviors.