In Ireland and the United Kingdom, housing associations are private, non-profit organisations that provide "social housing" for people in need of a home. Any budget surplus is used to maintain existing housing and to help finance new homes and it cannot be used for personal benefit of directors or shareholders. Although independent, they are regulated by the state and commonly receive public funding. They are now the United Kingdom's major providers of new housing for rent, while many also run shared ownership schemes to help those who cannot afford to buy a home outright.

Housing associations provide a wide range of housing, some managing large estates of housing for families, while the smallest may perhaps manage a single scheme of housing for older people. Much of the supported accommodation in the UK is also provided by housing associations, with specialist projects for people with mental health issues or learning disabilities, with substance misuse problems (alcohol or illegal drugs), the formerly homeless, young people, ex-offenders, asylum seekers, and people fleeing domestic violence.

In Australia, the term "housing association" refers to larger, growth-oriented 'not-for-dividend' community-housing providers. Smaller community housing providers may include trusts, cooperatives etc. State and territory-owned public housing represents about 80% of social housing in Australia. Over the years these public housing entities have had different names including: 'housing commissions', and 'housing trusts'.

Housing associations first appeared in the second half of the nineteenth century as part of the growth in philanthropic and voluntary organisations brought about by the growth of the middle classes in the wake of the Industrial Revolution. Early examples are the Guinness Trust, Peabody Trust and the Metropolitan Association for Improving the Dwellings of the Industrious Classes.

They increased in importance over the last decades of the twentieth century due to changes to council housing brought in by the Thatcher government, when rules were introduced that prevented councils subsidising their housing from local taxes, channelled grants for construction of new social housing to housing associations and allowed council tenants to buy their homes at a large discount. This, combined with cost-cutting initiatives in local government and a housing benefit scheme that was more generous to housing associations than local authorities, led to many councils transferring their housing stock to housing associations. These organisations are often referred to as large-scale voluntary transfer organisations or local housing companies.

The Housing Acts of 1985 and 1988 facilitated the transfer of council housing to not-for-profit housing associations. The 1988 Act redefined housing associations as non-public bodies, permitting access to private finance, which was a strong motivation for transfer as public sector borrowing had been severely constrained. These new housing associations were also the providers of most new public-sector housing. By 2003 36.5% of the social rented housing stock was held by housing associations. Currently, some of the biggest housing associations in the UK are Clarion Housing Group, Sanctuary Housing, L&Q and Peabody Trust, to name just a few. Some housing associations have partnerships with real estate investment trusts: Civitas Social Housing is the largest social housing real estate investment trust, working with 15 housing associations.

Housing associations may be constituted using various forms of legal entity. Many are industrial and provident societies, but there are also trusts, co-operatives and companies. They may or may not be registered charities.

Registered social landlord (RSL) is the technical name for social landlords that in England were formerly registered with the Housing Corporation, or in Wales with the Welsh Government. From 2010 to 2012, associations were termed registered providers under the Housing and Regeneration Act 2008, irrespective of status (private, public, for-profit or not-for-profit). As of 2012^[update], the terms registered social landlord and private registered providers of social housing are both used as alternative names for housing association.