The Leeds South by-election, 1892 was a parliamentary by-election for the House of Commons constituency of Leeds South in the West Riding of Yorkshire held on 22 September 1892.
The by-election was caused by the elevation to the peerage of the sitting Liberal MP, Sir Lyon Playfair. Playfair had been MP for Leeds South since its creation for the 1885 general election. In his letter to his constituency association informing them of his peerage, Playfair said it had been a wholly unexpected honour, a point later repeated in his memoirs and correspondence. Playfair was a distinguished chemist and expert in sanitation. He had worked closely with Prince Albert, the Prince Consort on a scheme for filtering sewage to fertilize the royal estate at Osborne House and later on plans for the Great Exhibition of 1851. As well as his past association with Price Albert, Playfair was a German speaker with strong Scottish connections so it was, perhaps, not surprising when he was created Baron Playfair of St Andrews and made Lord-in-Waiting to Queen Victoria.
The South Leeds Liberals held a selection meeting on 26 August 1892 and, having considered a number of possible candidates, they decided to invite John Lawson Walton to defend the seat. Walton was aged 40 and was a successful barrister on the north-eastern circuit who also had a practice in London. At the 1892 general election, just a few weeks earlier, he had been the Liberal candidate for Leeds Central when he lost narrowly to the sitting Conservative MP G W Balfour.