Imperial Brands plc., still commonly known by its former name (and now trade name) Imperial Tobacco, is a British multinational tobacco company headquartered in Bristol, England. It is the world's fourth-largest international cigarette company measured by market share after Philip Morris International, British American Tobacco and Japan Tobacco and the world's largest producer of fine-cut tobacco and tobacco papers. Imperial Brands is listed on the London Stock Exchange and is a constituent of the FTSE 100 Index.

Imperial Brands has 30 factories worldwide and its products are sold in around 120 countries. Its tobacco brands include Davidoff, West, Golden Virginia, Drum and Rizla. Imperial Brands's alternative nicotine products include the blu brand of electronic cigarettes, the Pulze and iD brands of heated tobacco systems, and the Zone X and Skruf brands of nicotine pouches.

Imperial Tobacco Canada is the Canadian subsidiary of British American Tobacco, and has no relationship to Imperial Brands. Similarly, Imperial Tobacco Company of India (now known as ITC Limited) is a separate company and has no relationship to Imperial Brands.

The Imperial Tobacco Company was created in 1901, in response to the price war in the British market promoted by "Buck Duke"'s American Tobacco Company. It amalgamated 13 British tobacco and cigarette companies: W.D. & H.O. Wills of Bristol (the leading manufacturer of tobacco products at that time), John Player & Sons of Nottingham, Stephen Mitchell & Son of Glasgow, and 10 other independent family businesses. The other, smaller companies, involved in the amalgamation included Lambert & Butler, William Clarke & Son, Franklyn Davey, Edwards Ringer & Bigg, Hignett Brothers, Hignett's Tobacco, Adkins & Sons, Richmond Cavendish, D&J MacDonald, and F&J Smith. In 1902 the printing and packaging firm, Mardon, Son & Hall was absorbed. In 1904, James & Finlay Bell Ltd was merged into the Stephen Mitchell & Son branch. The company's first chairman was William Henry Wills of the Wills Company.

In 1902, the Imperial Tobacco Company and the American Tobacco Company agreed to form a joint venture: the British-American Tobacco Company Ltd. The parent companies agreed not to trade in each other's domestic territory and to assign trademarks, export businesses, and overseas subsidiaries to the joint venture.

Imperial extended the tobacco growing enterprises in the United States that WD & HO Wills had developed before the amalgamation of 1901. It also established its own leaf-buying organisation in the US based at the Imperial Tobacco Warehouse in Durham, North Carolina; this is now owned, and has been renovated by Measurement Incorporated. It built the Imperial Tobacco Company Building at Mullins, South Carolina, between 1908 and 1913.

Whereas American Tobacco sold its share of BAT in 1911, a divestiture prompted by Supreme Court rulings in an anti-trust case, Imperial maintained an interest in British American Tobacco until 1980. In 1973, the Imperial Tobacco Company, having become increasingly diversified by acquisition of (amongst others) restaurant chains, food services and distribution businesses, changed its name to Imperial Group while tobacco products continued to be sold by a newly formed subsidiary named Imperial Tobacco Limited.

In 1986, the company was acquired by the conglomerate Hanson Trust plc for £2.5 billion. Divestments during the period of ownership by Hanson included Courage Brewery to Elders, Golden Wonder to Dalgety, Finlays to Arunbhai J. Patel, the wholesaling arm of Sinclair & Collis to Palmer & Harvey, Imperial Hotels and Catering to Trust House Forte and Ross Frozen Foods to United Biscuits. This also led to a dispute over pension payments to employees, as seen in Imperial Group Pension Trust Ltd v Imperial Tobacco Ltd. In 1996, following a decision to concentrate on core tobacco activities, Hanson de-merged Imperial and it was listed as an independent company on the UK stock exchange.