The company was founded by Sydney S. Guy (1885-1971) who was born in Kings Heath, Birmingham. Guy Motors operated out of its Fallings Park factory from 1914 to 1982, playing an important role in the development of the British motor industry.
Sydney S. Guy registered Guy Motors Limited on Saturday 30 May 1914, the same day he departed his position as Works Manager at the Wolverhampton company, Sunbeam. A factory was built on the site at Fallings Park, Wolverhampton. and by September 1914 production was underway on the newly designed 30cwt lorry. This employed a much lighter form of pressed steel frame, unlike the more commonly used heavy rolled steel channel frames of the time. This made the vehicle able to cross difficult terrain and a 14 seat poster bus built based on the design was used for crossing the Scottish Highlands.
From the mid-1930s, the company became increasingly involved in the British rearmament programme, developing and producing military vehicles. In 1935 Guy submitted their new four wheel Ant armoured car to military trials where it impressed and 150 were ordered by the government. After this success Guy began to concentrate solely on the production of military vehicles and by 1938 Guy relied exclusively on Government contracts and had ended civilian productions. During this time Guy designed a new armoured car, the Quad Ant, which was welded rather than riveted together. This development made armoured vehicles much safer and is reported to have saved the British government 100 million , earning Guy a commendation from the Royal Commission.
Guy armoured vehicles were used throughout the war, featuring prominently in the North African campaign and at the evacuation of Dunkirk. Although production of the Ant and Quad Ant were moved to Karrier the factory was still involved in the war effort producing anti-aircraft guns.