Maternal expressed emotion (EE), including maternal criticism and emotional over-involvement, is considered an index of family emotional climate that is critical for children’s psychological well-being. Limited research investigates how each element of EE differentially contributes to child behavior problems, or explores the mechanisms, such as child emotion dysregulation, through which parental EE influences child psychosocial outcomes. This study examined maternal EE, child emotion dysregulation, and child behavior problems among 60 mother–child dyads from a community sample, utilizing multi-method and multi-reporter assessment. Findings indicated that maternal expressed criticism toward the child was positively associated with child externalizing symptoms through its relation to increased child emotion dysregulation, whereas maternal emotional over-involvement was negatively associated with child externalizing symptoms through its negative relation to child emotion dysregulation. These results provided increased support for a model in which maternal criticism remains negatively associated with child psychosocial outcomes, but the construct of emotional over-involvement is not necessarily associated with youth psychosocial problems. This study also illustrated one pathway through which maternal EE influence child psychosocial functioning, thus placing EE research in the broader context of research on family emotion socialization.