This article addresses Early School Leaving (ESL) as a phenomenon that is identified in the EU and European countries such as Portugal as being the result of school disaffection that can be associated with social and educational problems. The relevance of this problem at the European level is highlighted by the large number of European guidelines on the matter and by the inclusion of ESL as one of the main questions to be addressed by the Horizon 2020. Based on interviews, this article questions possible relationships between how principals perceive both ESL and the measures to deal with it and the culture of the school as an identity of "differentia specifica" (ethos). It should be emphasised that the approaches of these principals to ESL and the school-based practices addressing it are quite diverse and relate to the ethos of the schools; students' trajectories and the complex relationship between education and the labour market. The principals manifest their investment and implication in the provision of adequate measures for their specific contexts and see teachers and external partners as key actors.