Violence against women and girls is an important global health concern. Numerous health organizations highlight engaging men and boys in preventing violence against women as a potentially impactful public health prevention strategy. Adapted from an international setting for use in the US, “Manhood 2.0” is a “gender transformative” program that involves challenging harmful gender and sexuality norms that foster violence against women while promoting bystander intervention (i.e., giving boys skills to interrupt abusive behaviors they witness among peers) to reduce the perpetration of sexual violence (SV) and adolescent relationship abuse (ARA). Manhood 2.0 is being rigorously evaluated in a community-based cluster-randomized trial in 21 lower resource Pittsburgh neighborhoods with 866 adolescent males ages 13–19. The comparison intervention is a job readiness training program which focuses on the skills needed to prepare youth for entering the workforce, including goal setting, accountability, resume building, and interview preparation. This study will provide urgently needed information about the effectiveness of a gender transformative program, which combines healthy sexuality education, gender norms change, and bystander skills to interrupt peers' disrespectful and harmful behaviors to reduce SV/ARA perpetration among adolescent males. In this manuscript, we outline the rationale for and evaluation design of Manhood 2.0.