In the most recent Programme for International Student Assessment of science learning, the equivalent of six school years separate the achievement of 15-year-olds in Finland, the best-performing country, from their counterparts in Kyrgyzstan, a former Soviet republic. Still more than a school year lies between the neighboring countries Canada, whose students perform well above the average of the principal industrialized countries, and the United States, with below-average performance. The fact only a modest part of these differences is accounted for by national wealth or investments in education has fueled the debate as to what is behind the high and equitable learning outcomes and rapid improvements observed in some countries. One area receiving increasing attention is how countries are redefining school leadership roles to drive improvements in learning outcomes and to responsibly manage increased school autonomy and accountability. PISA shows that a substantial proportion of students in countries belonging to the Organisation for Economic Co-operation and Development now attend schools in which school leaders have high degrees of autonomy in different areas of decision making. This article reports on OECD's comparative study in 22 countries in 2008, guided by research on leadership roles that are most conducive to improved teaching and learning, which shows that countries differ vastly in the achievement of their students as well as in the degree to which learning opportunities are equitably distributed. The study suggests that leaders' collaboration with other schools and with the local environment can improve problem solving through intensified interaction, communication and collective learning. It also can develop leadership capacity, stability and succession plans by increasing opportunities for local leadership in the school and at the local level.