The purpose of this study is to evaluate the impacts of ICT use on achievements by considering not only ICT use, but also the process and background variables that influence ICT use at both the student- and school-level. This study was conducted using data from the 2010 Survey of Seoul Education Longitudinal Research. A Hierarchical Linear Modeling (HLM) analysis was employed to control the student and school characteristics. The study results show that the use of ICT explained a significant portion in the overall variance in mathematic achievement at the elementary school level, at the middle school level, and at the high school level, respectively. Information communication and transactions, a component of ICT literacy, has negative impacts on mathematic achievement, and ICT self-efficacy is more likely to result in academic achievement than other background and processing variables. (Contains 4 tables.)