Children will be able to truly thrive in school and life if their mental well-being is supported, beginning in their early years. Amid growing international awareness about the importance of building the competency of those working with young children and their families, a particular concern focuses on increasing understanding of infant mental health. This article outlines the development and evaluation of a pilot infant mental health (IMH) training program for early years practitioners in Ireland. The program was developed by the Lets Grow Together! Infant and Childhood Partnerships in Cork, Ireland. The project translates and makes accessible IMH and early childhood development science and applies it to a format that will build capacity in the everyday practice of early years practitioners working in an area of high socio-economic deprivation. The training model is guided by the Irish Association for Infant Mental Health (I-AIMH) Competency Framework.®