Despite evidence that individual differences in defensiveness (typically measured with social desirability scales) may affect associations among self-report measures, little is known about the impact of defensiveness in the well-established relations between self-report emotion dysregulation and interpersonal problems. In Study 1 (community sample; N = 274), we found evidence that defensiveness significantly explained a portion of the shared variance between emotion dysregulation and interpersonal problems in the externalizing domain (i.e., interpersonal ambivalence, and aggression) but not in the internalizing domain. In Study 2, we replicated and extended these findings by showing that defensiveness accounted for a positive indirect effect of emotion dysregulation on aggression in a sample of #incarcerated offenders (N = 268). These findings are consistent with an increasing amount of research corroborating that defensiveness reflects meaningful variance – rather than a statistical nuisance – in relationships between self-reported ratings of emotion dysregulation, interpersonal problems and aggression. In both samples, reports of lower levels of emotion dysregulation were associated with higher levels of defensiveness. In turn, individuals with higher levels of defensiveness were more likely to report lower levels of interpersonal ambivalence and aggression. Therefore, defensiveness may play an important role in the mechanisms linking emotion dysregulation and associated negative consequences.