Purpose: The study seeks to examine the relationship between the implementation of the ISO 9000 quality management system and educational outcomes of schools, measured by student achievement on the state-mandated tests and school attendance rates--graduation rates, in the case of high schools. Design/methodology/approach: The study was conducted using schools in the USA that have implemented ISO 9000. The study employed the Hierarchical Linear Modeling (HLM) technique, taking into account the hierarchically nested data structure of this study. Findings: It was found that: first, there is no relationship between ISO 9000 participation and students' learning outcomes on the state-mandated tests: both for students in general and economically disadvantaged students in particular, across math and reading, and at all school levels; second, standardization of schooling by ISO 9000 fails to decrease the negative influence of school SES on the overall student achievement of a school; and finally, although ISO 9000 participation is not related to the students' graduation rates in high schools, it is positively associated with the students' school attendance rates in elementary and middle schools. Practical implications: Given the long-established institutional features of education such as value-orientation, diversity, and complexity, ISO 9000, focusing on procedural standardization of classroom activities, may not work well as a quick-fix solution to improve student learning. Originality/value: The study suggests that, by helping schools become organized and thus function well in the area of essential school operations such as student and teacher attendance, ISO 9000 could positively influence school performance without threatening other important values such as teachers' professional autonomy and creativity in classrooms. (Contains 5 tables.)