The Building Societies Association is the trade association for the UK's building societies. There are 58 building societies in the UK with total assets of over £360 billion. About 15 million adults have building society saving accounts and over 2.9 million adults are currently buying their own homes with the help of building society loans.

The BSA was established in 1869. It has two principal functions - to act as the central representative body for building societies and to provide information to its members. The BSA puts forward the industry view to government, parliament, regulators, the media and other interested bodies. It also provides information and advice to building societies on a range of relevant subjects.

There was substantial change in the building society sector in the mid to late 1990s, with a number of large societies giving up their mutual status and becoming banks, owned by shareholders. Mutual societies have only the interests of their member-customers to consider and have no shareholders to whom they need to pay dividends. Paying dividends generally adds about 35% to the overall costs of running a savings and mortgage business. Generally, this means that committed mutual building societies can offer more competitive rates of interest on mortgage and savings products.

The BSA offers advice and assistance on the whole range of issues affecting the operation of building societies, apart from some aspects of mortgage lending, which are looked after by the Council of Mortgage Lenders. The BSA is not a regulator - that is the role of the Financial Services Authority, nor does it deal with complaints about building societies - which are looked after by the Financial Ombudsman Service, if they cannot be cleared up by the society itself.