This study aimed to comparatively review student-level and school-level factors affecting scientific literacy in Singapore, Italy and Turkey. Two-level hierarchical linear modelling (HLM) was applied to the 2015 Programme for International Student Assessment data set. The findings show that (a) the enjoyment of science, interest in broad science topics and test anxiety are significant predictors of science literacy in the three countries; (b) the sense of belonging to a school was not a significant predictor of science literacy in any of the three countries; (c) student-related factors affecting school climate was a significant predictor of science literacy in all the three countries and (d) a shortage of educational material was a significant predictor of scientific literacy for Turkey and Italy, but it was not significant for Singapore. The implications of the findings obtained within the scope of the research are discussed in detail.