This study examined classroom discipline and its determinants through multilevel analyses of 107,975 students in 7,259 schools from 41 countries. In schools with proportionately more girls, better school discipline, higher achieving students, more teacher support, or better teacher-student relations, students reported better classroom discipline. Countries' economies and cultural values were linked to reported classroom discipline. In countries that were poorer, more equal, or had more rigid gender roles, students reported higher classroom discipline. Moreover, school variables' links to classroom discipline differed across countries. Specifically, in richer countries, teacher support and teacher-student relations had stronger, positive links to reported classroom discipline. In more equal countries, students' mathematics achievement had stronger, positive links to reported classroom discipline. Moderation effects of cultural values were also explored.Effective classroom discipline promotes students' learning and responsibility by facilitating quality instruction and helping students internalize self-discipline. Disruptive student behaviors interfere with teacher instruction and student learning by wasting instructional time on order and control (e.g., Infantino & Little, 2005), by creating an anxious classroom atmosphere (e.g., Bacon, 1990), and by raising teacher stress (e.g., Borg, Riding, & Falzon, 1991). By minimizing disruptive behaviors and encouraging responsible behaviors, effective classroom discipline not only allows teachers to provide quality instruction and enhance their psychological well-being (Borg et al., 1991), but also promotes students' sense of responsibility, academic achievement, and positive behavioral outcomes (e.g., Ma & Willms, 2004).