Abstract Issue/Problem Mental disorders are the main cause of years lived with disability (YLD) in 5-14-year-old people around the world, in Western Europe, and particularly in Portugal. Young people who experience anxiety during childhood have a 3,5-fold likelihood of suffering from depression or anxiety during adulthood. COVID-19 has aggravated this situation, namely regarding socio-emotional competencies. Description of the problem SELfit, a project based on the Socio-emotional learning (SEL) methodology, aims promoting mental health, by training teachers and community nurses to develop socio-emotional skills in students from primary schools. The project includes a theoretical and a practical/training session, and monthly supervision sessions by a team that includes a psychologist, a public health doctor and public health nurses. The period of implementation is between February to July 2022. Results A total of 8 community nurses and 13 teachers from 3 primary schools in Porto enrolled in this project, which corresponds to a total around 272 students from 5 to 8-year-old. Knowledge of nurses and teachers regarding mental health literacy, and social emotional learning was assessed, before and after the theoretical session. The mean percentage of correct answers before was 49% (54% regarding nurses and 45% teachers) compared to 84% (92% regarding nurses and 78% teachers) after. Concerning socio-emotional skills of the primary school students, possible improvement will be evaluated at the end of the project (July 2022). Lessons Mental health literacy and social emotional learning knowledge increased 35%, which highlights the importance of these theoretical sessions promoting mental health literacy. By the end of this project, it is expected to exist an improvement on socio-emotional skills of the primary school students. This is a very important project, expected to be implement and replicated in other schools in Porto and in Portugal. Key messages • Mental disorders are the main cause of years lost due to disability (YLD) in primary school students in Portugal; hence, it was chosen for this mental health promotion project. • This is a pioneer project in Porto, involving both community nurses and primary teachers, in which all are involved in training and promoting social-emotional learning in a school context.