Escalating armed violence in Haiti has driven large-scale internal displacement and sustained insecurity, exposures consistently associated with psychological distress. Despite the magnitude of this crisis, the mental health burden among internally displaced persons remains undocumented. This study aimed to examine the prevalence and factors associated with severe psychological distress among individuals displaced due to armed violence in Haiti. We conducted a cross-sectional survey among 1,545 internally displaced adults (60.5% women; mean age=36.5 years, SD=15.4) recruited from displacement camps and surrounding communities. Participants completed measures assessing psychological distress, exposure to community violence, perceived social support, resilience, and sociodemographic characteristics. Among the participants, 62.1% (95% CI: 59.6–64.5) reported severe psychological distress. Women had higher prevalence than men (65.2% vs. 57.4%) and markedly higher in rural compared with urban residents (80.2% vs. 54.9%). In multivariable analyses, rural residence (aOR=1.62, 95% CI: 1.01–2.61), lack of salaried employment (aOR=1.42, 95% CI: 1.01–2.01), and central region residence (aOR=11.56, 95% CI: 5.81–23.59) were associated with higher odds of severe psychological distress. Victimization of community violence increased the risk of experiencing severe psychological distress (aOR=1.17, 95% CI: 1.13–1.22), whereas social support (aOR=0.69, 95% CI: 0.59–0.80) and resilience (aOR=0.95, 95% CI: 0.94–0.96) decreased this risk. Due to gang violence in Haiti, internally displaced persons experience widespread severe psychological distress, shaped by exposure to violence and social vulnerability. A national mental health plan is urgently needed, as enhancing social support and resilience may buffer these effects, highlighting the need for integrated, trauma-and-resilience-focused, and context-sensitive mental health interventions.