The interactive model of language intervention instructs parents to use techniques that promote reciprocal social interactions and facilitate the development of communication and language abilities. In this evaluation study, 32 mothers and their preschool-age children with developmental delays were randomly assigned to treatment and control (delayed treatment) groups. Consistent with the interactive model, mothers in the treatment group became more responsive, less directive, and provided clearer linguistic models. Furthermore, these changes were maintained for at least 4 months after intervention, and involvement in the parent-centered intervention program did not increase maternal stress. More important, these changes were accompanied by concomitant increases in children's use of vocal turns. Contrary to predictions, developmental improvements in children's communicative and linguistic abilities were comparable in both groups. Findings suggest that an interactive model may afford a useful adjunct to other intervention approaches by instructing parents on how to promote children's use of existing abilities, but an interactive model may have no effect on language acquisition of at least some children with developmental delays.