<p>Two leading theories propose different reasons for men’s and women’s intimate partner violence (IPV). The gendered theory proposes that society’s patriarchal norms of male dominance and female subordination cause men’s IPV towards women. From this perspective, violence against ‘wives’ is condoned by society, and women only perpetrate IPV in self-defence against men’s primary violence. Conversely, the chivalrous theory of IPV explains women’s IPV perpetration in terms of society’s chivalrous norms, which protect women from male violence and emboldens women to physically assault male partners. From this perspective, women’s violence is not considered harmful to men. As gendered theory and chivalrous theory both reference stereotyped gender attitudes (sexism) towards women, I used the ambivalent sexism inventory (ASI) to test the competing theories efficacy in explaining IPV perpetration by heterosexual men and women. The ASI conceptualises sexist attitudes towards women as comprised of two parts: hostile sexism (reflecting the hostility towards women outlined by gendered theory), and benevolent sexism (reflecting the benevolence towards women outlined by chivalrous theory). Gendered theory states that society condones violence towards women. Thus, men’s attitudes approving of male-perpetrated IPV should mediate the relationship between men’s hostile sexism and IPV, if gendered theory predictions are correct. Alternatively, chivalrous theory poses that society does not approve of violence towards women. Thus, attitudes disapproving of men’s IPV against women and approving of women’s IPV towards men should mediate the relationship between benevolent sexism and IPV if chivalrous theory is correct. I hypothesized men’s increased hostile sexism would predict men’s increased IPV perpetration through increased approval of IPV against women, and men’s increased benevolent sexism would predict men’s decreased IPV perpetration through decreased approval of IPV against women. Further, I hypothesised that women’s increased hostile sexism would predict women’s increased IPV perpetration through increased approval of IPV against men, and women’s benevolent sexism would predict increased IPV perpetration through increased approval of IPV against men. North American men and women (N = 688) filled out an online questionnaire measuring experiences of IPV as victims and/or perpetrators, approval of male and female IPV perpetration, and hostile and benevolent sexism. Multi-group structural equation modelling tested the extent to which positive attitudes toward intimate partner violence mediated the association between sexism and IPV perpetration for men and for women. Results found that, for both men and women, increased hostile sexism predicted greater IPV perpetration through greater approval of men’s IPV against women. Furthermore, increased benevolent sexism predicted women’s increased IPV perpetration through increased approval of men’s IPV against women. Men’s increased benevolent sexism did not predict men’s lower IPV perpetration or disapproval of IPV against women. However, men’s and women’s ambivalent sexism also predicted greater approval of women’s IPV towards men. Results did not fully support patriarchal or chivalrous predictions, instead aligning well with ambivalent sexism theory which posits a more inclusive and holistic understanding of the relationship between sexism and IPV perpetration. Reducing all forms of sexism and men’s and women’s positive attitudes toward the use of IPV are identified as important targets for IPV treatment and prevention.</p>