W.O. Bentley founded Bentley Motors Limited on 18 January 1919 in Cricklewood, North London. Before the First World War, W.O. Bentley and his brother, Horace Millner Bentley, sold French DFP cars, but W.O. aspired to build his own designs. In 1913, inspired by an aluminium paperweight, he conceived of using aluminium to create lighter pistons; these were first utilized in Sopwith Camel aero engines during the war.
The company registered as Bentley Motors Ltd in August 1919 and exhibited a chassis with a dummy engine at the London Motor Show that October. Clive Gallop, a former Royal Flying Corps officer, designed an innovative four-valves-per-cylinder engine for the car. Although delivery was initially planned for June 1920, development delays pushed the first customer deliveries to September 1921.
Bentley's early reputation was built on the durability of the 3-litre model, which competed in hill climbs and at Brooklands. The company’s first major international event was the 1922 Indianapolis 500. Works driver Douglas Hawkes and riding mechanic H. S. "Bertie" Browning entered a modified road car, starting 19th and finishing 13th with an average speed of 74.95 mph.
In 1924, John Duff and Frank Clement secured Bentley's first victory at the 24 Hours of Le Mans. Despite this success, the enterprise remained underfunded. Woolf Barnato, heir to South African gold and diamond fortunes, intervened in 1925 by investing over £100,000 through his vehicle Baromans Ltd. This investment saved the workforce and gave Barnato control of the company as chairman.
During the late 1920s, a group of wealthy motoring enthusiasts known as the "Bentley Boys" maintained the marque's high-performance image. This group included Barnato, Sir Henry "Tim" Birkin, Glen Kidston, George Duller, Dudley Benjafield, and S.C.H. "Sammy" Davis. Many members possessed military backgrounds and independent wealth.
Under this influence, Bentley achieved four consecutive Le Mans victories from 1927 to 1930. The 1929 race was particularly dominant, with the Speed Six taking first place followed by 4½-litre models in second, third, and fourth. In 1930, Barnato famously raced and beat the "Blue Train" from Cannes to London in a Speed Six to win a £100 bet.
The development of the 4½-litre "Blower Bentley" by Tim Birkin remains a significant point of contention in the company's history. Birkin fitted a supercharger to the front of the car against the wishes of W.O. Bentley. While iconic, the Blower was uncharacteristically fragile compared to the 6½-litre workhorse. Its most notable result was Birkin's second-place finish at the 1930 French Grand Prix at Pau.
Following the 1930 Le Mans win, Bentley withdrew from motor racing, claiming they had learned enough regarding speed and reliability. The Great Depression subsequently throttled demand for luxury vehicles. By July 1931, the company entered receivership.
In 1931, Rolls-Royce purchased Bentley through a front called the British Central Equitable Trust for £125,000, outbidding Napier. Production moved from Cricklewood to Derby in 1933. The first model of this era, the 3½-litre, was a sporting variant of the Rolls-Royce 20/25 and was marketed as "the silent sports car." W.O. Bentley remained with the firm until 1935, when he left for Lagonda.
In 1938, a shadow factory was established in Crewe to produce Merlin aero-engines for the war effort. After 1945, Rolls-Royce moved all automobile production to Crewe. This era saw the introduction of the Bentley Mark VI in 1946, the first model offered with a factory-built "standard steel" body. In 1952, the R Type Continental was introduced, featuring coachwork primarily by H. J. Mulliner & Co.
Following the financial collapse of Rolls-Royce in 1970, the automotive division was spun off as Rolls-Royce Motors and later purchased by Vickers plc in 1980. Under Vickers, Bentley sought to reclaim its sporting heritage with the 1980 Mulsanne and the turbocharged Turbo R.
In 1998, Vickers sold Bentley and the Rolls-Royce motor car interests to Volkswagen AG for £430m, outbidding BMW. While Volkswagen acquired the Crewe factory and the Bentley brand, the rights to the Rolls-Royce name remained with Rolls-Royce plc, which eventually licensed them to BMW. A deal allowed Volkswagen to operate both brands until 2003, after which Volkswagen became the sole provider of Bentley vehicles.
Volkswagen invested nearly $2 billion in the revival of the brand and the modernization of the Crewe facility. This led to the 2003 launch of the Continental GT, a W12-powered coupé that signaled a significant increase in production volume.
Bentley's modern era has been marked by a shift toward higher production and new segments, including the 2016 launch of the Bentayga SUV. While the company suffered losses during the 2009 global recession and faced production halts during the 2020 COVID-19 pandemic, it recorded a 31% rise in global sales in 2021.
In November 2020, the company announced a strategic shift to become a fully electric brand by 2030. As of June 2024, the company is led by CEO Frank Steffan Walliser.
While primarily a luxury manufacturer, Bentley returned to official motorsport in the 21st century. The Bentley Speed 8 won the 24 Hours of Le Mans in 2003, marking the brand's sixth victory in the event. In 2014, a Bentley Continental GT3 entered by the M-Sport factory team won the Silverstone round of the Blancpain Endurance Series, representing the marque's first official entry in a British race since 1930.