Well-being in school is a dimension for overall life satisfaction and quality of life and is important for adolescents who are in a critical period of development and exposed to a variety of risk factors. This paper aims to analyze the relationship between resilience and well-being at school, focused on the role of socioeconomic status, using a quantitative approach. The results show that students who have the achievement motivation and grades significantly higher come from favoured families. These students tend to be more resilient, have a positive orientation towards the future, a better well-being expressed by positive indicators than those students belonging to medium or low-income families. But socioeconomically favoured students are less satisfied with school than with underprivileged students. Achievement motivation is an important predictor of well-being at school, both in middle and high schools. In high school students' sample, well-being (positive indicators) significantly explains satisfaction with school. In middle school students' sample, satisfaction with school is explained by resilience and, indirectness, through wellbeing expressed by negative indicators. Age-differentiated interventions that generate a supportive environment must be implemented for all: for students with low socio-economic status because they are less resilient and with lower overall wellbeing, but also for socio-economically favoured students, because they are less satisfied with school.