BACKGROUND: Although childhood trauma and violence against women are global public health issues, few population-based data from low-income and middle-income countries exist about the links between them. We present data from the UN Multi-country Study on Men and Violence in Asia and the Pacific, exploring the pathways between different forms of childhood trauma and violence against women. METHODS: In this multicountry study, we interviewed multistage representative samples of men and women, aged 18-49 years, in Asia and the Pacific, using standardised population-based household surveys. Men were interviewed in six countries, and women in four. Respondents were asked questions about their perpetration or experience of intimate partner violence or non-partner sexual violence, childhood trauma, and harsh parenting (smacking their children as a form of discipline). We used maximum likelihood multivariate logit models to explore associations between childhood trauma and violence against women, and fitted path models to explore associations between experience and perpetration of child maltreatment. FINDINGS: Between Jan 1, 2011, and Dec 1, 2012, 10 178 men and 3106 women completed interviews in this study, with between 815 and 1812 men per site and 477 and 1103 women per site. The proportion of men who experienced any childhood trauma varied between 59% (n=478, 95% CI 54·0-63·3; Indonesia rural site) and 92% (n=791, 89·4-93·8; Bougainville, Papua New Guinea). For women, the results ranged from 44% (n=272, 37·7-50·8; Sri Lanka) to 84% (n=725, 80·7-86·8; Bougainville, Papua New Guinea). For men, all forms of childhood trauma were associated with all forms of intimate partner violence perpetration. For women, all forms of childhood trauma were associated with physical intimate partner violence, and both physical and sexual intimate partner violence. There were significant, often gendered, pathways between men's and women's perpetration and experiences of childhood trauma, physical intimate partner violence, harsh parenting, and other factors. INTERPRETATION: The data point to both a co-occurrence and a cycle of abuse, with childhood trauma leading to violence against women and further child maltreatment, which in turn increases the risk of experience or perpetration of violence during adulthood. Efforts to prevent both forms of violence would benefit from a meaningful integrated approach. Interventions should promote positive parenting, address inequality and the normalisation of violence across the life course, and transform men's power over women and children. FUNDING: Partners for Prevention. National studies were funded by the UN Population Fund in Bangladesh and China, UN Women in Cambodia and Indonesia, UN Develoment Programme in Papua New Guinea, and CARE in Sri Lanka.