John Watson Laidlay FRSE (1808–1885) was a Scottish merchant, numismaticist and orientalist.
He was born on 27 March 1808 in Glasgow, the son of John Laidlay Esq. Of Fleetwood in Lancashire. His father was a businessman who travelled extensively. His mother was sister to the bankers and merchants J & R Watson and it is likely that John Laidlay worked for the firm. Watsons owned extensive indigo plantations in Bengal.
He was educated at a private school in Blackheath, London. He then studied Chemistry under Michael Faraday. He also studied Hindustani under Dr Gilchrist in London and there was introduced to Bishop Reginald Heber. Having been suitably trained he was sent to India in 1825 to represent his uncles in their Indian companies. This also linked to other company interests in the East India Company. The two had silk and indigo factories in Behrampore, Rampore-Beauleah, Surdah etc. J W Laidlay oversaw these factories until 1841. In 1839 he took an extended trip to the Straits Settlements in Malaysia for health reasons. Here he befriended Sir James Brooke.
In 1841 he moved to Moorshedabad in north-east Bengal. Here he became more settled. In 1844 he married Ellen Johnstone Hope, daughter of William Hope of Duddingston in Edinburgh. Together they went to live in Calcutta. He had a great love of ancient languages and coins, specialising in India and the Middle East. He published articles in the Journal of the Bengal Asiatic Society.