This paper builds and analyzes a new global macro-historical database of ef- fective tax rates on labor and capital in 155 countries. Effective capital tax rates fell in developed countries between 1965 and 2018, but rose in developing countries since the mid-1990s. Event-studies and instrumental variable regressions show that a significant share of the rise in developing countries can be explained by trade openness, which increases the share of output produced in large corpora- tions, where effective capital taxation is higher. In contrast to a commonly held view, globalization appears in many countries to have supported governments’ ability to tax capital.