Compared to other branches of the welfare state unemployment compensation was enacted later and in much lesser countries. This chapter examines the introduction and spread of unemployment compensation schemes across the globe until 1950. We argue that unemployment insurance was (and still is) the most controversial social protection scheme, which, in addition, is intimately tied to the existence of complementary institutions such as capitalist labour markets and employment exchanges. Programme adoption therefore only occurred in economically developed countries crucially facilitated by interstate war and deep economic crises. Both world wars and the Great Depression set-off shock waves across the globe, which not only created tremendous social needs but also opened a (short) window of opportunity for the introduction and reform of unemployment insurance.