Offspring of parents who have experienced interpersonal trauma are at increased risk of mental health problems. Because children learn to identify, express, and regulate their emotions through their parents’ emotion socialization practices, these parenting behaviors may be an important, modifiable target in the prevention of the intergenerational transmission of mental health risks within trauma-affected families. However, little is known about influences on parents’ socialization. The current study examines maternal and youth mental health as correlates and predictors of mothers’ supportive and unsupportive responses to their children’s negative emotional displays within a heterogenous community sample of 44 victims of interpersonal trauma and their 9–12-year-old children (M = 10.7 SD = 1.1). Mothers and youth reported on their mental health symptoms, emotion regulation, coping, and mothers’ responses to youth displays of negative affect. At baseline, all but one of the maternal and youth mental health characteristics examined were identified as significant correlates of mothers’ unsupportive responses. None of the characteristics were related to mothers’ supportive responses. Predictors of changes in maternal responses were examined in a longitudinal subsample (n = 30). Youth’s depressive, posttraumatic stress, and externalizing symptoms were associated with increases in mothers’ unsupportive responses. Youth adaptive emotion coping skills were associated with decreases in maternal unsupportive responses. Maternal self-efficacy was associated with increases in maternal supportive responses. The current study suggests that both increases in parent and youth adaptive functioning as well as reductions in maternal and youth symptoms are associated with more optimal maternal responses to youth affective displays.