Housing is often built by owner-builders, sometimes with the help of extended family, neighbours, or co-workers. ‘Aided self-help’ refers to the provision of assistance to owner-builders by government or nonprofit agencies. Assistance can take various forms, including advice, land, materials, and finance. As a policy, aided self-help emerged in the developed world in the early twentieth century. It was promoted for the developing world in the 1940s, and then the 1970s. Per capita costs are low, and the policy may enable households to build the dwellings they prefer. However, it may constrain what people build, depress wages, or discourage the development of a more efficient building industry.