Measuring treatment fidelity is an essential step in research designed to increase the use of evidence-based practices. For parent-implemented communication interventions, measuring the implementation of the teaching and coaching provided to the parents is as critical as measuring the parents’ delivery of the intervention to the child. Both levels of measurement are important in translating research into effective practice. In a single-case multiple-baseline design, the effectiveness of the teach-model-coach-review model for teaching Enhanced Milieu Teaching (EMT) Words and Signs to parents of young children with Down syndrome was evaluated. Implementation of parent training was completed with high fidelity. In addition, there was a functional relation between the implementation of the parent training and parents’ use of the specific EMT intervention strategies. The findings of this study replicate and extend previous studies suggesting systematic teaching and coaching can be effective in improving parent use of naturalistic communication strategies.