Purpose This study examined the nature of gender-based violence perpetrated in the aftermath of the 2011 Great East Japan Disasters and sought to develop recommendations for improving disaster response policies and programs.

Methods Using the key informant survey method, we collected data on incidents of violence against women and children after the Great East Japan Disasters. We excluded anecdotal information and reports from secondary sources. If the victim was a minor or otherwise dependent, we included cases that the informant heard from the victim’s family members (e.g., parent or guardian).

Results In addition to domestic violence, reported cases involved sexual assault, sexual harassment, and unwanted sexual contact perpetrated by non-intimates, many of which were targeted at women who were single, divorced, separated, or widowed. Perpetrators often exploited a sense of fear, helplessness, and powerlessness, including quid pro quo types of assault where threats were used to force compliance with sexual demands in exchange for shelter, food, and other life-sustaining resources.

Conclusions and Significance and Contributions to Injury and Violence Prevention Science This study elucidated various pathways through which the pre-disaster gender inequity predisposes women to the risk of gender-based violence in and after the disaster. Examination of post-disaster gender-based violence helps expose social mechanisms and power structures that contribute to and exacerbate women’s vulnerability to gender-based violence. This, in turn, allows for the development and implementation of prevention strategies that are aimed at altering socio-cultural-political mechanisms and power structures that disadvantage and discriminate against women.