Glasgow (UK: GLA(H)Z-goh, GLA(H)SS-; Scots: Glesca [ˈɡleskə] or Glesga [ˈɡlezɡə]; Scottish Gaelic: Glaschu [ˈkl̪ˠas̪əxu]) is the most populous city in Scotland and the fourth-most populous city in the United Kingdom, as well as being the 27th largest city by population in Europe. In 2020, it had an estimated population of 635,640. The city was made a county of itself in 1893, prior to which it had been in the historic county of Lanarkshire. The city now forms the Glasgow City Council area, one of the 32 council areas of Scotland, and is governed by Glasgow City Council. It is situated on the River Clyde in the country's West Central Lowlands.

Glasgow has the largest economy in Scotland and the third-highest GDP per capita of any city in the UK. Glasgow's major cultural institutions – the Burrell Collection, Kelvingrove Art Gallery and Museum, the Royal Conservatoire of Scotland, the Royal Scottish National Orchestra, Scottish Ballet and Scottish Opera – enjoy international reputations. The city was the European Capital of Culture in 1990 and is notable for its architecture, culture, media, music scene, sports clubs and transport connections. It is the fifth-most visited city in the United Kingdom. The city hosted the 2021 United Nations Climate Change Conference (COP26) at its main events venue, the SEC Centre. Glasgow hosted the 2014 Commonwealth Games and the first European Championships in 2018, and was one of the host cities for UEFA Euro 2020. The city is also well known in the sporting world for football, particularly for the Old Firm rivalry.

Glasgow grew from a small rural settlement on the River Clyde to become the largest seaport in Scotland, and tenth largest by tonnage in Britain. Expanding from the medieval bishopric and royal burgh, and the later establishment of the University of Glasgow in the 15th century, it became a major centre of the Scottish Enlightenment in the 18th century. From the 18th century onwards, the city also grew as one of Britain's main hubs of oceanic trade with North America and the West Indies; soon followed by the Orient, India and China. With the onset of the Industrial Revolution, the population and economy of Glasgow and the surrounding region expanded rapidly to become one of the world's pre-eminent centres of chemicals, textiles and engineering; most notably in the shipbuilding and marine engineering industry, which produced many innovative and famous vessels. Glasgow was the "Second City of the British Empire" for much of the Victorian and Edwardian eras.

In the late 19th and early 20th centuries, Glasgow's population grew rapidly, reaching a peak of 1,127,825 people in 1938. The population was greatly reduced following comprehensive urban renewal projects in the 1960s which resulted in large-scale relocation of people to designated new towns, such as Cumbernauld, Livingston, East Kilbride and peripheral suburbs, followed by successive boundary changes. Over 1,000,000 people live in the Greater Glasgow contiguous urban area, while the wider Glasgow City Region is home to over 1,800,000 people, equating to around 33% of Scotland's population. The city has one of the highest densities of any locality in Scotland at 4,023/km².