The article shows how judicial review has expanded around the globe from the United States, Western Europe, and Japan to become a regular feature of constitutional design in Africa and Asia. Although the formal power to exercise judicial review is now nearly universal in democratic states, courts have varied in the extent to which they are willing to exercise this power in practice. After decades of authoritarian rule, East Asia has experienced a wave of democratization since the mid-1980s. Transitions toward more open political structures have been effectuated in Korea, Taiwan, Thailand, Mongolia and Indonesia, and even the Leninist states of China and Vietnam have experienced tentative moves toward more participatory politics. These political transitions have been accompanied by an important but understudied phenomenon: the emergence of powerful constitutional courts in the region. Constitutional courts have exercised review to challenge political authorities when conflicts arise among government institutions or governments impinge on individual rights.