Intimate partner violence (IPV) is the leading form of gender-based violence globally and increases during times of conflict and displacement. To reduce IPV and encourage help-seeking, a two-phase community-based intervention was co-designed with Rohingya in Malaysia and Syrians in Lebanon. Three day workshops, utilizing a social norms-based mental health-integrated approach, were implemented for women and men in each country (n = 148). Pre- to post-measures indicated reductions in beliefs about acceptability of violence and rigid gender norms, and improvements in mental health, functioning, coping, and self-efficacy for women and men following workshop participation. Workshop participation was also associated with increased help-seeking intent, for both mental health and IPV (victims and perpetrators). Workshops included community design of poster campaigns to address IPV, which were then tested in each setting using a randomized controlled trial in Malaysia (n = 240) and a matched cluster comparison in Lebanon (n = 260). Women in both settings found IPV less acceptable in the poster condition. Help-seeking preferences were also influenced by the poster for women and men in both countries. This participatory intervention research can provide a roadmap for use in other settings, emphasizing the value of community-generated solutions to IPV among displaced populations.