The Woolwich Equitable Building Society (later Woolwich Building Society or The Woolwich) was a British financial services company founded in Woolwich in 1847 and remained a local institution until after the First World War when it began a modest regional expansion. This accelerated after the Second World War and the period from 1960 was notable for its acquisitions. Following deregulation, the Society diversified and became one of the largest national building societies.
In 1997 it demutualised and became Woolwich PLC. The company was listed on the London Stock Exchange. It was once a constituent of the FTSE 100 Index but was acquired by Barclays in 2000.