John William Muir (15 December 1879 – 11 January 1931) was the editor of The Worker, a newspaper of the Clyde Workers' Committee, who was prosecuted under the Defence of the Realm Act for an article criticising World War I.
He became involved in the Shop Stewards' Movement and was a member of the Clyde Workers' Committee, an organisation that had been formed to campaign against the Munitions Act, which forbade engineers from leaving the works where they were employed.
", Muir was jailed for twelve months, alongside Willie Gallacher.
In 1917, Muir joined the Independent Labour Party and became close to John Wheatley.
He lost his seat in the 1924 election after which he ran the Workers Educational Association until 1930.