Joseph Watson, 1st Baron Manton (10 February 1873 – 13 March 1922) was an English industrialist from Leeds, Yorkshire.

He was chairman of Joseph Watson & Sons Ltd, soap manufacturers of Leeds, and a director of the London and North-Western Railway, in the late 19th century the largest joint stock company in the world. He became in later life a pioneer of industrialised agriculture in England and a successful racehorse owner. He was step-great-grandfather to David Cameron, former Prime Minister of the United Kingdom.

Watson was the only son of George Watson, soap manufacturer, of Donisthorpe House near Moor Allerton, Leeds, Yorkshire. He was educated at Repton School and Clare College, Cambridge. He was recalled to the family firm before completing his degree, becoming chairman at a young age.^{[citation needed]}

Joseph went to work at his grandfather's company, Joseph Watson & Sons, and turned the company from the medium-sized concern built up by his father and uncle Charles into one which ruled the soap market of North-East England, with national and international sales, becoming William Lever's biggest rival.

On 4 August 1906 Watson and William Lever, by then the largest manufacturer, met in the Grand Hotel in London to finalise a plan to set up a "Soap Trust" which would merge the major soap manufacturers into a monopoly, thereby gaining economies of scale in advertising and production costs. Watson favoured the use of a parent company whilst Lever preferred a scheme of exchange of shares between participating companies to bind them together. This occurred during a period of many corporate trusts in the United States. The scheme was strongly opposed by the Daily Mail newspaper which campaigned for a boycott by its readers of the trust brands. Profits at participating firms were thereby severely reduced. The Northcliffe Press in its expanding and highly popular campaign overstepped the mark by falsely asserting trust soaps were made from scented fish oil. Although Watson and Lever won substantial libel damages from the press, losses in reputation and profits had been suffered all round. On the proposal of Watson and Crosfield, another large manufacturer, the scheme was abandoned in November 1906. By then Watson had already disposed of much of his shareholding, previously all held by himself and his uncle Charles, to William Lever, in exchange for Lever Brothers shares to set up the trust.

In 1912/13 Watson sold much of his remaining shareholding to Lever (Lever Brothers Ltd., later Unilever) and sold to him the remainder in July 1917, but remained as chairman. In July 1915 he had sold to Lever his half share in the Planter's Margarine Co Ltd, a joint venture established in November 1914 at Godley in Cheshire with Levers, in response to Government anxiety at the wartime loss of Dutch supplies, which by 1915 was the country's second largest margarine manufacturer. He had supplied it from his Olympia Oil & Cake Co. Ltd. at Selby, Yorks which operated the largest linseed oil crushing and refining plant in Europe. It also hardened whale oil and in 1917 during WWI was allocated by the government 21% (later 25%) of British whale oil for hardening. Watson then suffered substantial losses in an unsuccessful speculation in linseed, and he sold Olympia Oil & Cake to the Dutch firm Jurgens, which had outbid Levers.

Spurred on by wartime food shortages, Watson began pioneering industrialised agriculture, and he funded an "Agricultural Research Department" on his estate at Offchurch near Leamington Spa in Warwickshire. He founded the Olympia Agricultural Co Ltd and invested much of his money into agricultural and sporting estates totalling some 20,000 acres (81 km²) at Selby in Yorkshire, Manton Down (5,500 acres) in Wiltshire, Sudbourne Hall (9,000 acres) in Suffolk; Compton Verney and nearby Offchurch Bury (2,700 acres) both in Warwickshire; and at Thorney in Cambridgeshire.

His Olympia Oil & Cake Co. under the brand name "OCO" produced animal feed for dairy cows, calves, lambs and pigs, all from the new source of linseed oil. The company acquired sites near Selby within the parish of Barlby in 1909–10, and their buildings later dominated the road and river frontages. Soon after 1910 the company built the first "village estate" of workers' housing in the area, which was later expanded by other nearby employers. Before 1921 the Olympia Hotel opened near the site at Barlby Bank, taking its name from the company and using a sign showing seed-crushing machinery. The company in 1952 became part of British Oil and Cake Mills Ltd.