Before the First World War, W. O. Bentley and his brother Horace sold French DFP cars from a showroom in Cricklewood but W. O. wanted to design and build his own machines. At the DFP factory in 1913 he noticed an aluminium paperweight and realised the material could replace cast iron for pistons; the first Bentley aluminium pistons were subsequently fitted to Sopwith Camel aero engines during the war. Bentley Motors was formally founded on 18 January 1919 — the same day the Paris Peace Conference opened. First recruits were draughtsmen Harry Varley (formerly of Vauxhall) and Frederick Burgess (formerly of Humber). The company's core effort centred on a new 3-litre engine with an overhead camshaft designed by ex-Royal Flying Corps officer Clive Gallop. Delivery of the first cars, promised for June 1920, slipped to September 1921.
Bentley's first major international competition was the 1922 Indianapolis 500, where works driver Douglas Hawkes drove a modified road car to a 13th-place finish from 19th on the grid, averaging 74.95 mph over the full 500 miles. The team then returned immediately to England for the 1922 RAC Tourist Trophy on the Isle of Man.
The original 3-litre model was supplemented by a larger 6½-litre six-cylinder in 1926 as customers fitted heavier saloon bodies that the 3-litre engine struggled to pull. In 1927 a 4½-litre engine was created by removing two cylinders from the 6½-litre unit. In 1928 the lighter Speed Six variant was introduced; it would become arguably the most successful racing Bentley, achieving a 1-2-3-4 finish at Le Mans in 1929 and a 1-2 result in 1930.
Financial rescue came from Woolf Barnato, heir to a South African diamond fortune, who invested over £100,000 via his company Baromans Ltd beginning in May 1926, paid off all creditors, and became chairman. The Wall Street Crash of 1929 and the Great Depression killed demand for expensive cars. In July 1931 mortgage payments could not be met and a receiver was appointed. Rolls-Royce — acting through a front entity, British Central Equitable Trust — submitted a winning sealed bid of £125,000, with the true buyer's identity concealed from Bentley himself until the deal closed. Napier had believed it was the winning bidder for much of the process.
Rolls-Royce formed a subsidiary, Bentley Motors (1931) Ltd, taking over the Cricklewood factory, Cork Street showrooms, the Kingsbury service station, and the services of W. O. Bentley himself. Rolls-Royce had neglected to register the Bentley trademark so did so immediately after the acquisition. Production was suspended for two years before resuming at Rolls-Royce's Derby works. W. O. Bentley, unhappy with his diminished role, left to join Lagonda when his contract expired in April 1935.
When the Bentley 3½ Litre appeared in 1933 as a sporting derivative of the Rolls-Royce 20/25, it divided traditional customers but earned genuine praise, including from W. O. Bentley himself. Rolls-Royce's advertising described it as "the silent sports car." All Bentleys produced between 1931 and 2004 used inherited or adapted Rolls-Royce chassis and engines.
In preparation for World War II, construction of a shadow factory at Crewe — chosen for its road and rail links and distance from European bombing — began in July 1938 on 60 acres of farmland. The first Rolls-Royce Merlin aero-engine came off the line five months later; 25,000 were built and the factory employed 10,000 workers at its 1943 peak. After the war, car production transferred from Derby to Crewe.
To meet post-war export demand, Rolls-Royce developed the all-steel Bentley Mark VI, entering production at Crewe in early 1946 — the first Bentley with a complete factory body rather than a separate rolling chassis for coachbuilders. The R Type Continental, introduced in 1952, was aimed at the British market and featured fastback coupe coachwork predominantly by H. J. Mulliner; only around 164 examples plus a prototype were produced.
Financial collapse caused by development problems with the RB211 jet engine forced Rolls-Royce into receivership in 1970; the car division was separated as Rolls-Royce Motors Limited and sold to engineering conglomerate Vickers in August 1980. By that point Bentley sales had fallen so badly that less than 5 percent of combined output carried the Bentley badge. Vickers set about restoring the high-performance heritage, typified by the 1980 Mulsanne and later the turbocharged Turbo R. The strategy worked: by 1986 the Bentley-to-Rolls-Royce production ratio had reached 40:60; by 1991 the two marques had achieved parity.
In October 1997 Vickers announced it was selling Rolls-Royce Motors. BMW, which already supplied engines and components for both marques, made a final offer of £340 million. Volkswagen outbid it at £430 million, acquiring vehicle designs, nameplates, production and administrative facilities, and the Spirit of Ecstasy and Rolls-Royce grille shape trademarks — but not the rights to the Rolls-Royce name or logo, which were owned by Rolls-Royce Holdings plc. BMW separately paid Rolls-Royce plc £40 million to license the Rolls-Royce name for its own vehicle range, and from 2003 forward BMW established a separate Rolls-Royce Motor Cars at Goodwood in West Sussex.
Volkswagen modernised the Crewe factory substantially. The Bentley Continental GT, launched in the Volkswagen era, became a commercial cornerstone of the brand alongside the Flying Spur saloon and the Bentayga SUV. China became Bentley's largest single market by November 2012.
After a long absence from factory competition, Bentley returned to the 24 Hours of Le Mans and won in 2003, adding to the five victories of the 1920s. In the GT3 era, a Bentley Continental GT3 entered by the M-Sport factory team won the Silverstone round of the 2014 Blancpain Endurance Series — the marque's first official entry in a British race since the 1930 RAC Tourist Trophy.
The Cricklewood cars — the 3-Litre, 4½-Litre, Blower Bentley, Speed Six, 8-Litre, and 4-Litre — defined the original marque. Derby-era cars included the 3½-Litre, 4¼-Litre, and wartime Mark V. Crewe-era highlights include the Mark VI, R Type Continental, the S-series, T-series, Corniche, Mulsanne, Turbo R, Continental R and T, and the Azure. The current lineup is built around the Continental GT, Flying Spur, and Bentayga.