Intimate partner violence (IPV) is a ubiquitous and serious problem, the prevalence of which varies greatly around the world. Previous research shows that cultural factors interact with personality and that this interaction influences cognitions, attitudes, and behaviors that are related to personal and individual styles of resolving conflicts. In relation to this, the present study has three aims: comparing the self-reported IPV (physical, psychological and sexual) of English and Spanish offenders, comparing the Millon Clinical Multiaxial Inventory III (MCMI-III) scores of the two groups, and examining the association between country of origin, psychopathology, and IPV. The sample consists of 147 IPV offenders (80 English and 67 Spanish). The measures used were the MCMI-III and the Conflict Tactics Scale 2. The Mann–Whitney U tests were used to compare the English and Spanish sample, and independent logistic regressions were used to examine the relationship between personality patterns, psychopathology and culture, and IPV. Higher frequencies of physical and psychological aggression were found in the English group compared with the Spanish group as well as several differences in personality patterns and psychopathology between the groups. Some MCMI-III subscales also interact with nationality and predict physical and psychological aggression. The relevance of these results for intervention is discussed.