Armstrong Siddeley

1919-1959 aerospace and automotive manufacturer in the United Kingdom

1959-1968 aircraft engine manufacturer in the United Kingdom

British automobile pioneer (1866-1953)

right|thumb|1912 Siddeley-Deasy 18-24 Althorpe Special Cabriolet The Siddeley-Deasy Motor Car Company Limited was a British automobile, aero engine and aircraft company based in Coventry in the early 20th century. It was central to the formation, by merger and buy-out, of the later Armstrong Siddeley Motor and Armstrong Whitworth Aircraft companies.