The initial results of the Programme for International Student Assessment (PISA) indicated that Finnish and Swedish students are among the best readers in all OECD countries. However, the literacy performance of 7% of Finnish and 12% of Swedish students remains at a level which is not sufficient for further studies or active citizenship. This article reports a further comparative study which explores, compares and contrasts, by means of two-level logistic regression models, students' personal, socio-economic and cultural factors and their effects on low as opposed to average reading literacy achievement in Finland and Sweden. The results indicate that the risk of being a low achiever is strongly determined by gender and by several sociocultural factors as well as by students' personal characteristics, attitudes and activities both at and outside school. The constructed model was relatively similar and predicted with approximately equal degrees of probability membership in the risk group in both countries. This lays a solid foundation for joint pedagogic developmental efforts.