This Final Report to the Australian Institute of Teaching and School Leadership (AITSL) presents the products and findings of research conducted to provide expert advice, and design and develop an Assessor Training Program for national certification of Highly Accomplished and Lead teachers. The research design and development of the Assessor Training Program, the associated expert advice and the Final Report were underpinned by participatory qualitative methodologies, informed by international research findings and delivered by a proven, highly respected and experienced research team from the SiMERR National Research Centre at the University of New England.