Indonesia’s successful democratization poses a puzzle. As a vast, lower-middle income country with scant tradition of open politics, Indonesia did not seem to be a good bet for robust democracy. But Indonesia enjoys an advantage: extraordinary levels of civic engagement. Indonesians participate in organizations at unusually high rates and display an exceptional level of interpersonal sociability. Spirited associational life has enabled Indonesians to constrain elites and sustain self-government by cultivating a sense of efficacy, fostering the cultivation and transfer of civic skills, and creating opportunities for individuals to be recruited into politics. Indonesia demonstrates how civic engagement can abet democratization.