In the post-war period, the mass provision of social rental housing units represented the primary means for resolving housing welfare issues across much of Western Europe. In contrast to North America, large swathes of state subsidized rental housing where built and let-out at submarket rents, both to needy as well as regular working households. By the 1980s social housing accounted for as many as four in ten homes in some contexts. Since then however, these important welfare sectors have been under attack. On the one hand, privatization policies have continued to undermine the basis of social renting with home ownership and private rental sectors advanced by policy as preferable alternatives. On the other hand, social housing providers have been restructured in order to play a more residual role in the housing market and serve more targeted groups of socially vulnerable people. This paper assesses key differences in the development of West European social housing sectors as well as recent transformations in their status that represent a challenge their sustainability. It also looks to what insights this provides for the South Korean housing context where public housing has proliferated and been increasingly diversified in recent years.