This paper investigates the effects of school mobility on the academic achievement of four cohorts of students in the Houston Independent School District (HISD). In addition to distinguishing between within-year and between-year mobility, this study accounts for all schools students have attended, and it explores mobility effect differences by race/ethnicity. Using a multiple membership model (MMM), the findings suggest that within-year school mobility compromises students’ academic achievement more than between-year school mobility. Black students have the highest mobility rate both for between-year mobility and within-year mobility. In addition, although Asian-American students achieve higher reading and math scores on average than other groups, they experience a stronger negative impact from within-year school mobility than any other group. This finding suggests that Asian American is a diverse ethnic group in terms of socioeconomic status, a result contrary to the “model minority” image that many people believe. In one part of my study I found while some Asian-American students such as Chinese and South Koreans outperform white students in academic performance, those from Nepal, Bhutan, and a few other Asian regions fall behind other students. The conclusion contains implications for policy making and suggestions for future research.