Primary school provides an appropriate opportunity for children to commence comprehensive relationships and sexuality education (RSE), yet many primary school teachers avoid teaching this subject area. In the absence of teacher confidence and competence, schools have often relied on health promotion professionals, external agencies and/or one-off issue-related presentations rather than cohesive, systematic and meaningful health education. This study examines the implementation of a 10-lesson pilot RSE unit of work and an accompanying assessment task in two primary schools in South-East Queensland, Australia. Drawing predominantly from qualitative data, the research explores the experiences of primary school teachers as they engage with RSE curriculum resources and content delivery. The results show the provision of a high-quality RSE curriculum resource grounded in contemporary educational principles and practices enables teachers to feel more confident to deliver RSE and minimises potential barriers such as parental objections and fear of mishandling sensitive content.