Red Clydeside was the era of political radicalism in Glasgow, Scotland, and areas around the city, on the banks of the River Clyde, such as Clydebank, Greenock, Dumbarton and Paisley, from the 1910s until the early 1930s. Red Clydeside is a significant part of the history of the labour movement in Britain as a whole, and Scotland in particular.

Glasgow is the most populous city in Scotland, the third-most populous city in the United Kingdom, and the 27th-most populous city in Europe. In 2022, it had an estimated population as a defined locality of 632,350 and anchored an urban settlement of 1,028,220. Glasgow became a county in 1893, the city having previously been in the historic county of Lanarkshire, and later growing to also include settlements that were once part of Renfrewshire and Dunbartonshire. It now forms the Glasgow City Council area, one of the 32 council areas of Scotland, and is administered by Glasgow City Council.