The Abarth OT 1300 was a racing car produced between 1965 and 1966.

The Ferrari 250 GTO may have been heralded for winning the Division 3 World Touring Car Championship but the Fiat Abarth OT 1300 nearly matched its performance in Division 1. Over 50 cars were made.

This small car won many important victories for Abarth including the 1966 and 1967 Division 1 World Championships. The car was based on Simca parts and used a heavily modified Simca chassis from the Simca 1000. The engineer Mario Colucci was responsible for the design. Fixed to the chassis were a new front and rear sections that supported independent suspension and modified Fiat 850 components.

The engine was designed from the ground up but was similar to the Simca 1.3-litre that had been used in previous years. The engine was built at Corso Marche and by Luciano Fochi who had already designed the 1.6 and 2.0-litre units. Hallmarks of the engine included five main bearings, twin overhead cams and twin choke Weber carburettors.

The whole car was covered in a sleek fibreglass body that was penned Mario Colucci and fabricated at Sibona & Basano of Turin. At the front was a large opening to feed air to the radiator, cooling the engine. The air was then extracted out the top of the hood. Both the front and rear sections were hinged and provided ample access to the running gear.