Purpose: This study presents a cost-effectiveness analysis of a targeted selective pre-school intervention programme, "Happy Talk", which focuses on language development, by simultaneously enhancing parental interaction and the pre-school environment.Method: Happy Talk (delivered to 77 children) is an add on intervention, and is compared to usual care, adopting a healthcare perspective. Cost-effectiveness analyses were carried out using the Pre-school Language Scale 5- Total (PLS-5) for baseline analysis and the Child Health Utility Instrument (CHU9D) in a secondary analysis.Result: Baseline cost-effectiveness analysis showed Happy Talk was more effective (6.3 point change in total PLS-5 standard score - effect size 0.463SD and more expensive (€82.06) than usual care (cost-effectiveness ratio is €13.02 per unit change). Employing a proxy to estimate monetary net benefit, the benefits outweigh the costs, showing that it is cost-effective. However, results do not persist when health-related quality of life outcome measures are considered.Conclusion: Findings suggest a targeted selective public health approach, could be considered value for money to reduce the societal burden of children with low levels of speech, language and communication. However, measurement of longer term outcomes and a larger trial are required, to definitively inform policy changes.