Mothers of children with intellectual disability were assessed at two time points, 2 years apart (n = 75 at Time 1, n = 56 at Time 2). Data were gathered on maternal distress, mental health, expressed emotion, and the child's internalizing and externalizing behavior problems. Consistent with previous research with families of children who have intellectual disability, maternal distress and children's behavior problems entered into a bidirectional relationship over time. This relationship was found to be specific to externalizing problems. Exploratory analyses also suggest that maternal distress and depression had a bidirectional longitudinal relationship. In terms of maternal expressed emotion, criticism and not emotional over-involvement was cross-sectionally but not longitudinally related to children's externalizing behavior problems and to maternal distress.