The Upper Clyde Shipbuilders Work-in was a famous act of industrial action in the early 1970s in Scotland. In the early twentieth century the River Clyde was the main centre of ship-building in the world. By the early 1970s there were around 8,500 men working in only five shipyards on the river organised into the Lower and Upper Clyde Shipbuilders. This stark decline left some with the distinct impression that the UK government did not care about maintaining it as an industry (if not even leading some to believe that they were deliberately running it down).

In 1971 the Upper Clyde Shipbuilders went into receivership and the then Tory government under Edward Heath refused it a £6m loan. This provided stark evidence of government indifference to the industry and the trade union leadership decided to act. Rather than go on strike, which was the traditional form of industrial action, the union leadership decided to have a 'work-in' and complete the orders that the shipyards had in place. In this way they dispelled the idea of the workers being 'work-shy' and also wanted to illustrate the long-term viability of the yards.

The work-in was led by two young shop stewards, Jimmy Reid and Jimmy Airlie, both of whom were then members of the Communist Party of Great Britain. They ran a well organised campaign in which the shop stewards in each yard remained firmly in charge. Reid wanted to ensure the workers projected the best image of the yard workers he possibly could, and insisted on tight discipline. He famously addressed the workers at the yards where he instructed them that there should be "no hooliganism, no vandalism and no bevvying (drinking)".

Reid's tactics worked and public sympathy in the Glasgow area and beyond was on the side of the workers who took part. This was backed up with massive demonstrations in Glasgow, one of which was attended by around 80,000 marchers. At one demonstration Tony Benn addressed those in attendance, and Billy Connolly (himself a former shipyard worker) offered entertainment to the gathered crowd. The campaign was also well backed financially, and at one meeting for the campaign Jimmy Reid was able to announce that the campaign had received a £5,000 contribution from Lennon, to which an attendee replied "but Lenin's deid! (dead)".

The campaign also attracted support from various political parties, mainly the Labour Party and the Scottish National Party.

The work-in was successful in the short-term. In February 1972 Heath's Government relented and retained two of the yards and sold off another. However the industry has continued to decline and there are now even fewer yards open on the Clyde than there were at the time of the work-in.

Some commentators have remarked though that the work-in was hugely successful at halting the laissez-faire free-market ideas that many in the then Tory government wanted to implement (and which the later Thatcher Tory government would go on to do). Some have also noted the huge success in which the way the work-in galvanised public support in the way that other industrial disputes failed to do (the Miners Strike in the 1980s divided opinion a lot more for example).