Project ImPACT is a parent-mediated social communication intervention for young children with ASD that was developed in community settings to encourage dissemination. A single-subject, multiple-baseline design was conducted across 8 preschoolers with ASD and their mothers to examine the efficacy of the model for improving parent intervention fidelity and child spontaneous language. Multilevel modeling was used to examine the relationship between parent fidelity and child language within session. All parents increased their use of the intervention techniques. Improvements in spontaneous use of language targets were observed for 6 of the 8 children. There was a significant association between parents' use of the intervention strategies and their child's spontaneous language use.