Although cross-national evidence suggests that decentralization of educational governance is positively related to student achievement, related research often fails to recognize the separate roles and influences of governments, school boards, principals, and teachers. We use data from the 2015 Programme for International Student Assessment to examine school leaders' perceptions of governance arrangements across 68 countries and to assess whether differences in perceived governance patterns are significantly related to differences in student achievement. We find that although school governance arrangements vary substantially across countries, increases in teacher decision-making responsibilities are consistently and positively related to student achievement in math, reading, and science, all else equal. Furthermore, controlling for school principals' leadership style does not fundamentally change the positive and significant relationships between teacher decision making and student achievement, suggesting that the impact of teachers may be independent of school principals' attitudes and actions.