Employing data from TIMSS 2011, this study investigated the association among middle school students' in-class computer use, content learning opportunities, and mathematics and science achievement. 3,398 students and 183 mathematics teachers and 3,989 students and 363 science teachers were included in the study. Structural equation modelling was used to analyze the data. The mathematics results suggested that in-class computer use was associated indirectly with mathematics achievement because teachers provide greater content learning opportunities. In contrast, the science results showed no significant relation between in-class computer use and students' achievement. Further, our study found that using computers in class as an information tool moderated the socioeconomic status-science achievement association. Computer integration into mathematics and science classrooms is discussed.