The Building Societies Association is the trade association for the UK's building societies. There are 65 building societies in the UK with total assets of around £175 billion. About 15 million adults have building society saving accounts and about 2.5 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, the media and other interested bodies. It also provides information and advice to building societies on a range of relevant subjects.

There has been great change in the building society sector in recent years, with a number of large societies giving up their mutual status and becoming banks. Mutual societies have only the interests of their customers to consider and have no shareholders to whom they need to pay dividends. Generally, this means that committed mutual building societies can offer more competitive rates of interest on mortgage and savings products.