Evidence illustrates that insecure romantic attachment predicts higher levels of relational aggression. However, no research has attempted to explain that relationship with mediating variables, such as relationship power, which is associated with attachment and partner violence. Data for this study included 457 couples from Wave 2 of the Flourishing Families Study. Actor Partner Interdependence results indicated that insecure attachment was significantly predictive of relational aggression actor effects. There was also a significant partner effect between male insecure attachment and female relational aggression, and power was a significant mediator between attachment and relational aggression for males and females.