Engaging men and boys as participants and stakeholders in gender-based violence (GBV) prevention initiatives is an increasingly institutionalized component of global efforts to end GBV. Accordingly, evidence of the impact of men’s engagement endeavors is beginning to emerge, particularly regarding interventions aimed at fostering gender equitable and nonviolent attitudes and behaviors among men. This developing evidence base suggests that prevention programs with a "gender transformative" approach, or an explicit focus on questioning gender norms and expectations, show particular promise in achieving GBV prevention outcomes. Interventions targeting attitude and behavior change, however, represent just one kind of approach within a heterogeneous collection of prevention efforts around the globe, which can also include community mobilization, policy change, and social activism. The degree to which gender transformative principles inform this broader spectrum of men’s engagement work is unclear. The goals of this article are twofold. First, we offer a conceptual model that captures and organizes a broader array of men’s antiviolence activities in three distinct but interrelated domains: (1) initial outreach and recruitment of previously unengaged males, (2) interventions intended to promote gender-equitable attitudes and behavior among men, and (3) gender equity-related social action aimed at eradicating GBV, inclusive of all genders’ contributions. Second, we review empirical literature in each of these domains. Across these two goals, we critically assess the degree to which gender transformative principles inform efforts within each domain, and we offer implications for the continuing conceptualization and assessment of efforts to increase men’s participation in ending GBV.