"Children’s long term success at school is influenced as much by social, emotional and self-regulation skills as by academic skills and knowledge. Social and emotional development is a main contributor to successful school transitions and a significant preventative factor of disruptive behaviour, and mental health difficulties. Not paying attention to social and emotional development is harmful to young children’s capacity to learn and to thrive. The SEED Project (Social and Emotional Education and Development) was designed to draw attention to the importance of social and emotional well-being for children’s learning and development. This was done by a research study about young children's well-being and the factors that influence it in ECEC and primary schools in Croatia, Hungary, Latvia, Norway and the Netherlands. Based on the research findings practitioners working with 3 to 6-year-olds in these countries participated in a continuing professional development pathway based on group reflection to give them the skills to create create educational environments which are supportive of children's social and emotional well-being.The participants were 140 ECEC practitioners and primary school teachers and 44 principals in Croatia, Hungary, Latvia, Netherlands and Norway who participated in the research. A subset of 80 of these professionals participated in the piloting of the WANDA group reflection over one school year, supported by trained mentors. They also took part in study visits to ECEC settings. Other participants were the 545 staff of faculties of teacher education in universities and institutes of teacher education, teachers' and parents' associations, university researchers and local and national policy makers responsible for education and training. These participated in local seminars and conferences where SEED findings and their implications were discussed. Achievements of SEED include an assessment of the socio-emotional well-being of 1195 five-year-old children attending ECEC settings in urban and rural areas in 5-countries; a comparative analysis in understandings of young children’s social and emotional development across countries; sensitization of practitioners, principals, teacher trainers and policy makers to the importance of social and emotional well-being and the multiple setting factors that influence it and the formulation of principles of social and emotional well-being in ECEC.Important results are that practitioners are strengthened in their professional role and where their attention should be oriented in order to support socio-emotional well-being of children. This means they are better able to deal with daily challenges in their classrooms. Practitioners also feel supported in concretely transforming and improving daily practice and in continuously working on the link between theory and practice. The group reflection pathway has also better prepared practitioners to deal positively with diversity in their classrooms by drawing attention the impact ECEC environments. and their behaviours and interactions with children and their parents have on social and emotional wellbeing. SEED has therefore led to quality improvements in ECEC. It has also led to concrete commitments to give more attention to social and emotional wellbeing in training, practice and policy in all participating countries. ""Everyone is accepted as he/she is. This is what we stand for as a school. New children are immediately included. We take care of children when they show emotional needs. We teach children to play together and to talk to each other about difficulties"". (Practitioner, the Netherlands). The results of SEED are available in two publications, 1) a research report titled: ""Social and Emotional Wellbeing of Young Children in ECEC Settings"", which is also available in summary in Croatian, Dutch, English, Hungarian, Latvian and Norwegian, and 2) guidelines for coaches and mentors, titled ""SEEDs of Change: Supporting social and emotional well-being of children in Early Childhood Education and Care"", and summaries in Croatian, Dutch, English, Hungarian, Latvian. Paying more attention to young children's feelings and social relationships in ECEC and primary school leads to happier learners who have a better and a more equal chance to fulfil their potential. As a result of this project ECEC centres and schools are now better prepared to meet the needs of all children and their families.For more information and to download the SEED publications: https://icdi.nl/projects/social-and-emotional-education-and-development-seed"