Objective: When mothers who have survived intimate partner violence separate from their partners, they often turn to family court for help with a range of issues from division of assets to child custody arrangements. Often, however, they face ongoing legal abuse when abusive partners use court processes to further enact coercive control and judicial betrayal, when judges fail to prevent such harms and/or add to the mistreatment. Although both processes may undermine survivors’ mental health, existing research on this topic is limited and no known research has explored the relationship between the two constructs. To address this gap, we explored the direct association between legal abuse and mental health, as well as the possible mediating role of judicial betrayal. Method: In a sample of 218 family law-involved survivor-mothers who responded to a survey, we explored the relationship between legal abuse and mental health and the mediating role of judicial betrayal in that relationship. Results: Legal abuse was related to elevated symptoms of both posttraumatic stress disorder and depression even after controlling for prior psychological, physical and sexual abuse, and demographic variables. Further, associations between legal abuse and mental health were mediated by one of the two dimensions of judicial betrayal (Missing the Abuse), though not by the other (Mistreating the Survivor). Conclusion: Findings highlight the profound damage associated with legal abuse, especially when it is mediated by judicial betrayal. They underscore the key role that judges can play in protecting survivor-mothers’ mental health in family court.