A substantial amount of research indicates that academic self-concept is a function of both individual characteristics, and school effects that impact on the development of self-perceptions. Few studies have studied a cohort of students as they progress through the transition from elementary to middle school. The present study uses multi-level modeling to examine school effects on students’ academic self-concept in reading and math as they transition from elementary to middle school. Data come from the ECLS-K data set. Few school effects were found, but students’ SES was found to be a strong moderator of the relationship between reading achievement and self-perceptions of students’ ability and interest in reading.