BackgroundIn August 2014, the Islamic State of Iraq and Syria (ISIS), a terrorist organization, attacked the Yazidi’s ancestral homeland in northwestern Iraq. Among other atrocities, they abducted thousands of women and girls and traded many of them into sexual slavery. The aim of this study is to determine the mental health of women and girl survivors of these events in relation to enslavement and experiences with genocide-related events, as well as perceived social rejection in their community.MethodsBetween February and July 2017, trained local assessors interviewed a sample of 416 Yazidi women and girls (65 of whom had survived sexual enslavement), aged between 17 and 75 years, and living in internally displaced person camps in the Kurdistan Region of Iraq. Post-traumatic stress disorder (PTSD) and depression symptoms were assessed using validated Kurdish versions of standard instruments. Scales for trauma exposure and perceived rejection were developed for the purpose of this study.ResultsParticipants reported a high number of traumatic events. More than 80% of girls and women, and almost all participants who were formerly enslaved, met criteria for a probable DSM-5 PTSD diagnosis. Trauma exposure and enslavement predicted poor mental health. In addition, among formerly enslaved girls and women, perceived social rejection in their community mediated the relationship between traumatic enslavement events and depression symptoms.ConclusionsIn a context of maximum adversity, enslavement and war-related events contribute to high levels of PTSD and depression. Perceived social rejection seems to play a role in the relationship between trauma exposure and mental health among abducted genocide survivors. Providing psychosocial support and treatment for Yazidi people is essential and urgently required.Electronic supplementary materialThe online version of this article (10.1186/s12916-018-1140-5) contains supplementary material, which is available to authorized users.