Increasing physical activity opportunities in schools has emerged as a global priority among school-aged youth. As a result, many countries have designed and implemented whole-of-school physical activity initiatives that seek to increase physical activity opportunities that are available to school-aged children before, during, and after school. Considering the comprehensive school physical activity program conceptual framework, this article includes a discussion of the initiatives from four countries: Finland (Finnish Schools on the Move), Ireland (Active School Flag), Poland (PE with Class), and the United States (Let's Move Active Schools). Background information, implementation strategies, best practices, development opportunities, and relevant research from each country will be presented. Exploring different perspectives sheds some light on the international landscape relative to whole-of-school physical activity promotion and provides direction for future and continued research and practice.