Childhood internalizing problems may occur as early as preschool, tend to be stable over time, and undermine social and academic functioning. Parent emotion regulatory behaviors may contribute to child internalizing problems and may be especially important during the preschool years when parents model emotion coping and regulation for their children. Parents who feel out of control of their preschoolers' behavior and emotional states may adopt avoidant emotion regulatory strategies. We proposed that parent depression, perceived locus of control, and experiential avoidance would be linked with internalizing symptoms in a high-risk sample of preschool-aged children. We also expected that locus of control would mediate the relationship between maternal depression, experiential avoidance, and child internalizing problems. Seventy-four urban, low-income, diverse mothers of Head Start preschool children completed rating scales measuring their own depression, locus of control, experiential avoidance, and their children's internalizing behaviors. Correlational analyses revealed that mothers reporting higher levels of depression were more likely to report experiential avoidance, feeling out of control in their parenting role, and internalizing symptoms in their children. Hierarchical multiple regressions showed that locus of control explained additional unique variance in child internalizing problems over and above that explained by maternal depression. Locus of control mediated the relationship between maternal depression and child internalizing symptoms. The importance of considering parent locus of control and its relation to children's internalizing symptoms is discussed as a potential target for early childhood prevention programs. (Contains 1 figure and 3 tables.)