Background: Childhood trauma/adversity is pervasive and has far-reaching consequences for children’s health and well-being, leading to increased calls for trauma-informed practice (TIP). Archival data show that early Montessori schools (circa 1907-1917) were recognised as ‘healing’ schools, wherein trauma-affected children improved dramatically. Aims/objectives: This project aimed to (1) investigate claims of psychological healing in early Montessori schools; (2) integrate the findings with contemporary knowledge on TIP; (3) develop a novel Continuing Professional Development (CPD) programme based on this integration; and (4) evaluate its perceived impact on staff in a test school. Method: A multi-method, three-strand approach was used comprising three distinct and sequential studies. Study 1 involved a documentary analysis of eyewitness testimonies, media reports, and Montessori’s own accounts of her early schools, to investigate how the Montessori approach supported trauma-affected children. Study 2 integrated the findings of Study 1 with contemporary trauma literature to develop an innovative CPD programme designed to enhance the capacities of early childhood teachers to support trauma-affected children. Study 3 then used a case study approach to provide a rich contextual account of teachers’ (n=11) experiences of engaging with this programme, focusing on its perceived impact on their knowledge, attitudes/beliefs, professional practice, and their views on its feasibility. Findings: Study 1 identified significant evidence of psychological healing in trauma-affected children attending Montessori’s early schools. Study 2 found that several features of Montessori education cohere with contemporary research on TIP approaches, especially the Neurosequential Model in Education (NME), and that these can be integrated to develop a programmme of Montessori-attuned TIP. Study 3 found that early childhood/Montessori teachers rated the new programme highly, stating it positively impacted their practice. Conclusion: This project makes a significant original contribution to existing knowledge on Montessori pedagogy and TIP and has important implications for supporting trauma-affected children in Ireland and elsewhere.