The TaxPayers' Alliance (TPA) is a pressure group in the United Kingdom which was formed in 2004 to campaign for a low-tax society. The group had about 18,000 registered supporters as of 2008 and claimed to have 55,000 by September 2010. However, it has been suggested that a vast majority of these supporters – who do not contribute financially or engage in campaigning – were simply signed up to a mailing list.

Questions have been raised about the funding of the organisation and there is speculation that significant contributions are received from overseas. The TPA was given the lowest possible grade for financial transparency by Who Funds You, a British project that seeks to rate and promote transparency of funding sources of think tanks. It has also been questioned whether the group has links to similar organisations based at 55 Tufton Street in Westminster.

The group was founded by political strategist Matthew Elliott, who founded Eurosceptic think tank Business for Britain as well as Conservative Friends of Russia, Big Brother Watch and the NOtoAV campaign during the 2011 Alternative Vote referendum. In 2015, Elliot was appointed chief executive of the Vote Leave campaign to promote a British withdrawal from the European Union.