Comparative welfare state research is directed mainly toward the development of welfare states in advanced democracies, although the majority of people live outside the OECD and often face graver social risks arising from poverty and starvation. To secure a minimum standard of living, nearly all countries have introduced social programs to protect their citizens. Yet the timing of when governments take on the responsibility of providing social protection varies decisively across the world. Using data for 177 territories and independent states over the period from 1820 to 2013, we illustrate how social security legislation has emerged throughout the world. Although we find that the patterns and pathways vary strongly between different regions, the evidence shows that the proliferation of social protection is a transnational event: regional diffusion and membership in the International Labour Organization matter irrespective of the regional and temporal context.