Who rules in provinces around the world? Provincial executives play an increasingly important role in domestic politics as central governments devolve more and more political, fiscal, and administrative authority to subnational units. Leaders of provincial polities not only directly influence governance in their own units, but develop intergovernmental relations with other provincial leaders and central governing elites that shape politics across national territory and at multiple scales of government. Moreover, provincial leaders have increasingly developed diplomatic relations with other countries, suggesting greater potential to shape and be shaped by international relations. Despite the growing importance of provincial executives in multiple political arenas, a comprehensive understanding of these leaders, their interactions, and outcomes has been stunted by lack of comparative data. This project constructs the Provincial World Leaders (PWL) dataset and tackles questions related to the selection and governing outcomes of subnational political executives. PWL identifies all political executives governing second-tier subnational units from 1989-2017, tracking biographical characteristics and political variables like party affiliation, leader entry/exit, and tenure. This project is in the early stages and data collection is currently underway.