Cheating is a more or less prominent feature of all educational contexts, but few studies have examined its association with aspects of school effectiveness theory. With recently collected data from upper-secondary school students and their teachers, this study aims to examine whether three aspects of school effectiveness—school leadership, teacher cooperation and consensus, and school ethos—are predictive of student’s self-reported cheating, while also taking student- and school-level sociodemographic characteristics as well as student grades and moral standards into consideration. The study is based on combined data from two surveys: one targeting students and the other targeting teachers. The data cover upper secondary schools in Stockholm and includes information from 4529 students and 1045 teachers in 46 schools. Due to the hierarchical data, multilevel modelling was applied, using two-level binary logistic regression analyses. Results show significant negative associations between all three aspects of school effectiveness and student cheating, indicating that these conditions are important to consider in the pursuit of a more ethical, legitimate and equitable education system. Our findings also indicate that the relationship between school effectiveness and student cheating is partly mediated by student grades and moral standards.