Description: School is central to the daily life of most youngsters. During school hours they obtain a lot of knowledge and many skills, but, above all, they grow and develop a conception of themselves as individuals as well as members of social groups. Most students participate actively in school life, and develop a sense of belonging. Their friends are there, they have good relations with teachers and other students, and they identify with and value schooling from the future perspective. But many students are not engaged. They do not believe their school experience has much bearing on their future, and they do not feel accepted by their classmates and teachers. Gradually these students may withdraw from school life, and become disaffected from school. Can we identify schools where students have high levels of affective and social engagement, and if so, what factors contribute to their success? What is the relationship between student engagement and academic performance? How students' engagement is associated with their educational aspiration? These questions which are of great concern to educators in the Nordic countries, are dealt in our study that exploits the PISA 2003 data gathered from the representative samples of 15-year-old students in all Nordic countries. The PISA data include information on students' affective and social engagement in school life which is operationalised from the viewpoint of three aspects: students' sense of belonging to school, students' relation to their teachers and students' perception of how well school prepares them for life. Methodology: Students' engagement profiles of different Nordic countries are first compared and then further analysed by using two-level-modelling to reveal the factors behind students' engagement and its effects in reading, mathematics and science performance as well as in aspiration for further studies. Special attention is focused on engagement differences between Nordic countries and between schools within each country. Differences between countries are first examined in five separate models, which are further combined into one two-level model. Differences within the country are investigated in the socio-cultural frame examining effects of some student background characteristics, such as gender, self-esteem, immigrant status and socio-economic background, and effects of some school level factors, such as size of the school, average socio-economic level and ratio of immigrant students at school. Conclusions: The findings on the similarities and differences in Nordic students' engagement in school life will hopefully lay a foundation for joint pedagogic developmental efforts to improve students' well-being and learning at school.