Around half of the people incarcerated in the United States are parents to children under the age of 18. Incarceration can have adverse consequences on family members and strain coparenting relationships. Unfortunately, traumatic events often occur during imprisonment, and/or trauma from previous experiences may be exacerbated in incarcerated settings causing posttraumatic symptoms to add further stress to coparenting relationships during incarceration. This study uses data from the Multi-Site Family Study of Incarceration, Parenting and Partnering to assess the relationship between PTSD symptoms and coparenting relationships from the perspective of incarcerated coparenting fathers. The results provide limited evidence that having PTSD symptoms is associated with a higher relative risk of coparents not supporting each other’s decisions and not making the most important decisions together regarding their shared child. Clinical implications and directions for future research are discussed to improve coparenting relationships in justice-involved families.