School innovativeness determines the vitality of schools as learning organizations. However, schools markedly vary in innovativeness, and research is needed to account for this variability. The present study provides a theoretical account of this variability based on an uncertainty management perspective. Conceptualizing participative decision-making as an organizational routine through which uncertainty is shared and collectively managed, we hypothesize that participative decision-making is conducive to the school's organizational capacity to foster innovation. Our hierarchical linear modeling analysis of 7507 schools in 41 countries lends support to this hypothesis. The findings demonstrate that the level of school innovativeness tends to be higher in schools that make greater use of participative decision-making. This pattern was observed in all countries examined, and the pattern was even clearer in countries with a stronger cultural orientation toward uncertainty avoidance. Although further research is needed, this study concludes that participative decision-making can promote school innovativeness by facilitating the distributed management of uncertainty.