Early School Leaving (ESL) is a challenge that concerns countries all over the world. This is because it directly affects both the lives of the students who drop out and society in general. This study investigates Primary Education teachers, Compulsory Secondary Education teachers, and Baccalaureate teachers' perspectives of school dropout factors and the perceived inspiring practices to prevent ESL. The study is based on qualitative methods and included interviews with 15 teachers and 3 focus groups. The results indicate that the factors considered most related to the ESL are those linked to individual and family characteristics (exogenous to the educational system such as national origin, ethnicity, social class, etc.). To a lesser extent, teachers' activities and attitudes and potential school-related causes (endogenous) are considered factors associated to ESL. Regarding inspiring practices, teachers reported mostly experiences at the instructional and relational level (micro level). However, teachers seem to be less aware of the institutional/systemic level of prevention of ESL (macro level). The study further argues the need to implement practices addressed to all students to retain more children at school rather than special programmes for special students (migrants, gypsies, students with special capacities, etc.). Teacher training that considered all the variables that can contribute to ESL is discussed.