Walter Owen Bentley, MBE (born 16 September 1888 – died 2 August 1971) was the founder of Bentley Motors. He was often known as W. O. Bentley or just "W.O."

Bentley in 1912 joined his brother, Horace Millner ("H.M.") Bentley, in a company called "Bentley and Bentley" selling French DFP cars. 

After the war, he founded his own motor car company, Bentley Motors, in 1919. W.O. designed a high-tech four-cylinder engine and sturdy chassis, the Bentley 3 Litre. Its durability earned widespread acclaim. 

His motto was, "To build a good car, a fast car, the best in class." 

Later he worked for Lagonda, Aston Martin and Armstrong Siddeley.