This study investigated the multilevel dimensionality of socioeconomic status and its relationship to reading achievement in 23 countries. Different factor structures of SES were found at different levels observations and in different countries. The study showed that the cultural dimension strongly related to student reading performance, while the school general capital dimension explained a large part of the between-school reading achievement differences. Most interestingly, the factor relationship between SES and reading achievement at the school level varies greatly across countries. It was argued that these variations might be due to the differences in the centralized versus decentralized educational finance, tracking mechanism and some social characteristics in different countries.