Intimate partner violence (IPV) within heterosexual relationships is a major concern worldwide due to the extensive negative impact on victims, and broader societal costs in terms of associated public health and criminal justice system expenses. Despite the pervasiveness of IPV and the damage caused by it, substantial knowledge gaps remain in the literature. My thesis contributes to a better understanding of IPV via two main aims: (1) to add to the understanding of men’s and women’s IPV through the novel application of cognitive, social, and attitudinal constructs, and (2) to provide insights to the societal responses to the most severe and common form of IPV, men’s violence toward women. These aims target five knowledge gaps within the existing literature. First, despite rationalization (a cognitive defense that provides self-justification of undesirable thoughts, feelings, and behaviors), being a key variable within the relational goal pursuit theory (Cupach et al., 2000) of obsessive relational intrusion (a form of agression often expressed in IPV), it has been overlooked in the literature. Second, the association between IPV and important relationships outside of attachment (e.g., friends, family, colleagues) has been underexplored. Third, although the literature recognizes that women can perpetrate IPV, the focus has been on male perpetration, and it remains unclear if the factors that contribute to IPV perpetration are similar for men and women. Leading from the focus on men as perpetrators, the fourth knowledge gap is the literature’s focus on men’s gendered attitudes (such as sexism) toward women, with little exploration of women’s gendered attitudes in relation to IPV perpetration. Fifth, and finally, preliminary evidence suggests sexism could be associated with societal responses to IPV, although this has not been well investigated, particularly in relation to the most severe form of IPV, men’s violence toward women. In this thesis, I explore these knowledge gaps in three empirical chapters. Study 1 (Chapter 4) presents research conducted with 379 participants (46% women) aged 18 – 72 years (M = 34.4, SD = 9.6) that assesses whether relational goal pursuit theory provides a more comprehensive account of obsessive relational intrusion when rationalization is included. A measure of rationalization is developed, and both men’s and women’s perpetration of obsessive relational intrusion is assessed. Results show that rationalization meaningfully contributes to relational goal pursuit theory and has the strongest association (of the relational goal pursuit variables) with obsessive relational intrusion. Thus, the findings of Study 1 add to the existing knowledge of obsessive relational intrusion behaviors for both men and women and establish the relevance of rationalization to such behavior. Study 2 (Chapter 5) builds on the findings of Study 1 by applying rationalization within the context of a novel model of broader IPV perpetration. The model explains men’s and women’s IPV perpetration by positioning rationalization with negative cross-gender contact (i.e., negative interactions between men and women; contact theory; Allport, 1954) and gender-based attitudes (i.e., hostile sexism; Glick & Fisk, 1996, 1999). Three relevant cross-gender contact relationship contexts are identified (romantic, caregiver, and general/platonic relationships) with three separate measures developed to capture these conditions. The model is assessed using a sample of 886 adults (50.6% women) aged 18 – 77 (M = 37.33, SD = 11.72). In all three cross-gender contact conditions, findings show the model to be supported for men’s and women’s IPV, with hostile sexism and rationalization sequentially mediating the association between negative cross-gender contact and IPV perpetration. A major contribution of these findings is that rationalization is highlighted as relevant to a broad array of IPV behavior (beyond obsessive relational intrusion). Further, findings highlight an association between negative experiences with the “other” gender (through hostile sexism and rationalization) and IPV for both male and female perpetrators. From Study 2 (Chapter 5), it is clear the way men and women engage with and view each other in general society plays a role in IPV perpetration. Chapter 6 (Study 3) then focuses on societal factors that might contribute to a culture of acceptance of the most common and severe form of IPV, men’s violence toward women. Drawing on the findings of Study 2, it is proposed that men’s and women’s gendered attitudes (i.e., hostile and benevolent sexism) toward women have relevance beyond the perpetration of IPV, such that individuals with higher levels of sexism toward women will be less likely to think men should be educated to not be violent toward women and more likely to think that women should be educated to avoid men’s violence. This premise is investigated drawing from 21,937 adults (62.6% women) aged 18 – 97 years (M = 49.62, SD = 13.93) who participated in Wave 8 of the New Zealand Attitudes and Values Survey. Findings are nuanced. For the idea that men should be educated to reduce men’s violence, those who endorse hostility toward women in breach of the status quo (i.e., higher hostile sexism) tend to disagree, whereas those who believe women to be in need of men’s protection (i.e., higher benevolent sexism) are more likely to agree. In contrast, for the idea that women should be educated to avoid men’s violence, those with higher levels of hostile sexism or benevolent sexism are more likely to agree. Interestingly, the pattern of results is similar for men’s and women’s responses. These findings are supportive of the notion that sexism could drive responses to men’s violence toward women that overlook men’s responsibility to abstain from violence and amplify women’s responsibility to keep themselves safe. Overall, this is a novel series of studies that introduces important cognitive, social, and attitudinal constructs to the IPV field. The findings provide unique insights to IPV perpetration by both men and women and also extend these findings to responses to men’s violence toward women. These findings have several important implications, including the potential of rationalization to be a focus in clinical IPV interventions, and the value of targeting men’s and women’s gendered attitudes in the campaign to improve public support for strategies to reduce men’s violence toward women.