Objective: This study examines whether fluctuation in mothers’ posttraumatic stress symptoms (PTSSs) predicts fluctuation in child adjustment problems in families seeking services for intimate partner violence (IPV). Method: Participants were 300 mothers (mean age = 30.65 years) of children (mean age = 6.88 years; 49% female) who were seeking shelter or legal services because of IPV. Most mothers identified as Hispanic (57%), followed by Black/African American (26%). Mothers reported PTSSs on a 7-item screening measure and reported child externalizing and internalizing problems on the Child Behavior Checklist. Mother and child functioning were assessed shortly after the mothers’ requested services and then every 4 months for a 5-year period. Results: Eighty-one percent of mothers reported clinical levels of PTSSs at the initial assessment. As hypothesized, fluctuation in mothers’ PTSSs predicted fluctuation in child externalizing and internalizing problems during the ensuing 4-month period. These relations, however, occurred within subjects but not between subjects. The within-subject associations emerged after accounting for IPV and mothers’ depressive symptoms and were stronger for older children than younger children. The strength of the associations decreased over time. Conclusions: Addressing women’s trauma symptoms at the point of seeking services for IPV has possible implications for child mental health. Attempting to reduce mothers’ PTSSs may have positive effects for women as well as their children.