ENReading literacy is considered the foundation of education, and there are many related factors contributing to it. The aim of the thesis was to study the role of learning strategies in explaining differences in reading literacy performance, discovering the sources of variation, and revealing the extent of school accountability for individual differences in reading literacy performance. The PISA 2009 data were chosen for the current analyses due to a unique combination of reading proficiency tests and student responses on learning strategies, including the metacognition- the higher level thinking ability, which has been found to have a powerful effect on learning results. The background factors (socio-economic and cultural status, gender, school language) and classroom environment factors (teacher-student relations and disciplinary climate) were included. The school language was added due the worrying situation of schools with different instructional language showing different results both in Estonia and Finland. Latvia, Lithuania and Estonia as Baltic countries, and Sweden, Norway and Finland as Nordic countries were in the study. The multilevel modeling was used to discover the factors explaining systematic differences, and to take the group effect (individual results depending on the group the person belongs to) into account. It became evident that metacognitive learning strategies are strong predictors of reading literacy achievement, and one of the strongest sources of systematic variation, even after the group effect was taken into account and the effect of other influential variables was controlled for.All the learning strategy variables together explained 56-67% of differences between schools, and about 30% of differences between students. In all studied countries the differences between students are partly dependent on the differences between schools: in Finland the smallest 9%, Norway 10%, Sweden 16%, Estonia 21%, Latvia 23% and Lithuania 32%. The between-school differences are seen as serious issue discrediting the equality of education. The students of Baltic countries reported greater use of traditional learning method such as memorization, but according to the regression analysis, applying memorization would less likely end up with success in reading. Metacognition also plays important role in explaining the differences among boys and girls in schools with different instructional language. When contextual factors were controlled for, the student awareness of learning strategies still explained about 22– 27% of between-student variation. In Finland the girls’ reading results appeared to be dependent on learning strategies, while in Estonia the opposite– student awareness of learning strategies explained more of boys’ variation of reading test results.