The hours we work are determinants for how life is structured in the modern world and set the boundary for leisure against work. This paper documents how working hours have become globally standardized through public policy and introduces a novel dataset on working-time regulation for 197 territories between 1789 and 2021 with 1,147 reform events. Today, 95% of territories regulate hours, representing a massive increase from 0 at the start of the 19th century. The data show that extensive regulations were enacted in colonial dependencies starting in the 1920s. This raised the question, What drives adoption of working-time regulation in colonies? I argue that colonial administrators adopt labor regulation to justify continued imperial rule in the face of new international standards and norms. Descriptive and regression results support this conclusion, with the long-term effects of colonization persisting today.