Affordable housing is housing which is deemed affordable to those with a household income at or below the median as rated by the national government or a local government by a recognized housing affordability index. Most of the literature on affordable housing refers to mortgages and a number of forms that exist along a continuum – from emergency homeless shelters, to transitional housing, to non-market rental, to formal and informal rental, indigenous housing, and ending with affordable home ownership.

Public housing is a form of housing tenure in which the property is usually owned by a government authority, either central or local. Although the common goal of public housing is to provide affordable housing, the details, terminology, definitions of poverty, and other criteria for allocation vary within different contexts. Within the OECD, social housing represents an average of 7% of national housing stock (2020), ranging from ~34% in the Netherlands to less than 1% in Colombia.