John McLaren (17 August 1831 – 6 April 1910), Lord McLaren, was a Scottish Liberal politician and judge.
The son of Duncan McLaren, a former Provost of Edinburgh and Member of Parliament, he was born in Edinburgh. He attended Edinburgh University before being admitted to the Scottish bar in 1856. He held the office of Sheriff of Chancery in Scotland 1869-1880. He reorganised the Scottish Liberals and arranged Gladstone's Midlothian campaign of 1879-1880.
McLaren wrote a number of books on legal topics, including 'Law of Wills and Succession.
He was elected Member of Parliament for Wigtown Burghs in April 1880 and appointed Lord Advocate, losing his seat on seeking re-election on 20 May 1880. He failed to be elected at Berwick-upon-Tweed on 21 July 1880, but was returned for Edinburgh on 28 January 1881. McLaren's father Duncan McLaren had resigned as MP for Edinburgh, which produced the vacancy to be filled. McLaren continued to sit for Edinburgh until he was appointed as a judge, later in the year.
Under pressure from Gladstone and Sir William Harcourt, he accepted appointment to the bench in 1881 with the judicial title Lord McLaren. He was an eminently successful judge, and edited works on Scots law. He was also a student of astronomy and mathematics, and was awarded honorary degrees from Edinburgh University, the University of Glasgow and the University of Aberdeen.