Providing all students with equal access to education and removing obstacles to learning especially among students from disadvantaged backgrounds have been leading principles in Nordic education policy. How successful have the Swedish and the Finnish - both Finnish and Swedish-speaking - school systems been in evening out individual, socio- economic, language and cultural discrepancies in reading literacy learning? Do the schools provide all students with similar opportunities to learn? Which factors increase the risk of low literacy achievement both at school and individual levels? To what extent do the determinants differ between Finnish and Swedish low achievers; and what are the similarities and the differences? These questions are significant in that they contribute to the identification of at-risk students, who are in most need of support and of enrichment of the learning environment as well as of remedial instructional strategies to decrease and prevent the risk. The paper presents further comparative analyses on the Finnish, both Finnish and Swedish speaking, as well as Swedish students' data collected in the PISA 2003 study from the representative samples of 15-year-old students. Swedish-speaking students in Finland were oversampled, which enables comparative analysis of the two language groups. The initial results of PISA 2003 indicated that both Finnish- and Swedish-speaking students in Finland and Swedish students are among the best readers in all OECD countries. However, the reading literacy performance of six per cent of Finnish-speakers and seven per cent of Swedish-speakers in Finland as well as 13 per cent of Swedish students had serious difficulties in using reading as an effective tool to advance and extend their knowledge and skills in other areas. Even though these students were not illiterate they were not able to construe meaning when information is not prominent. In addition, there were another 15 per cent of Finnish- speakers and 18 per cent of Swedish-speakers in Finland as well as 23 per cent of Swedish students who were capable of basic reading tasks and low-level inferences but who did not reach the proficiency level (3) which was considered as sufficient for further studies and active citizenship in the knowledge society. This article reports a secondary study on the Finnish and Swedish PISA 2003 data and explores, compares and contrasts, by means of two-level logistic regression model, students' personal, socio- economic, language and cultural factors and their effects on low as opposed to sufficently good reading literacy achievement in Finland and Sweden. Discovering the key determinants of low achievement is the first step towards remedying lack of sufficient skills. Based on the findings, both pedagogical and policy implications are discussed.