This research sets out to evaluate the impact of LEGO® Based Therapy on the development of skills and quality of life for people with neurodevelopmental disorders, as well as for those close to them. Widely used in the United States and the United Kingdom for almost 20 years, LEGO® Based Therapy was developed by Daniel Le Goff, psychologist licensed in Florida and New Jersey who has practiced for over 20 years with children, adolescents and adults with developmental disabilities, including autism, Asperger's syndrome and congenital disabilities, as well as acquired and traumatic brain injuries. Daniel Le Goff has extensive experience as a consultant and expert witness, as well as in direct clinical services, including applied behaviour analysis, cognitive behaviour therapy and cognitive rehabilitation. In 2008, Gina Gómez de la Cuesta completed her PhD at the Centre for Autism Research at the University of Cambridge, where she led and evaluated LEGO®® Based Therapy under the supervision of Daniel LEGO®ff, Simon Baron-Cohen and Ayla Humphrey. She is a teacher and psychologist by training and has worked at the National Autistic Society as Head of Action Research. She founded Play Included in 2018, with support from the Cambridge Social Ventures incubator programme, University of Cambridge to support children's development through play and promote LEGO®Therapy. Initially designed to improve the social skills of people with autism spectrum disorders but no intellectual disabilities, its effectiveness has been demonstrated by studies targeting this specific population. However, no research has yet been carried out in France on its application to a wider population, including various forms of neurodevelopmental disorder. Furthermore, existing studies have not considered the impact on the quality of life of beneficiaries and their families, which this thesis sets out to examine.