Unite the Union, commonly known as Unite, is a British and Irish trade union which was formed on 1 May 2007 by the merger of Amicus and the Transport and General Workers' Union (TGWU). Along with Unison, Unite is one of the two largest trade unions in the UK, with over 1.2 million members in construction, manufacturing, transport, logistics and other sectors. The general secretary of Unite is Sharon Graham, who was elected on 25 August 2021 with 46,696 votes on a turnout of 124,127, with her term beginning on 26 August 2021.

The Transport and General Workers' Union was one of the largest general trade unions in the United Kingdom and Ireland – where it was known as the Amalgamated Transport and General Workers' Union (ATGWU) to differentiate itself from the Irish Transport and General Workers' Union – with 900,000 members. It was founded in 1922 and Ernest Bevin served as its first general secretary.