An AB single-subject design replicated across five participants was used to assess the effects of an intervention that taught parents to support their preschool children's communication skills and manage their behaviour. Children with language delays and emergent behavior problems and their parents from low-SES backgrounds participated. Parents attended 30 individual sessions and were taught to be responsive to their children's communication and to provide contingent consequences for their children's behavior. Generalisation to interactions at home and maintenance of intervention efforts were assessed. Parents learned the strategies, generalised these strategies to interactions at home, and maintained positive changes 6 months after the intervention. Children showed positive changes in language and behavior during the intervention, but maintenance and generalisation of these effects were more variable.