Like the Aprilia and Aurelia, the Flavia too soon had a little sister. The Fulvia is almost identical in specifications to the Flavia and some parts are even interchangeable. Apart from the size, the biggest difference between the two cars is the engine. The Fulvia has the traditional V4 engine, of course of an entirely new design, with two overhead camshafts. The engine is slanted 45° to the left and almost all Fulvias have two double-choke carburettors. The Berlina is of an extremely angular design but it was soon joined in 1965 by the Fulvia Coupé, both designed and built in house. The Coupé is a most elegant design, it sold in large numbers and is today the most frequently seen Fulvia model. It was highly successful in competition despite a weight handicap and in 1972 it won Lancia their first World Rally Championship.

A different and more expensive coupé was available from Zagato, called the Sport. It is a beautiful little car, more accessible that most Zagato designs and commercially their biggest success. The first series had an aluminium body but later ones were all-steel and in total nearly 7000 are built.
The Fulvia was introduced with an 1.1 litre engine, the first Coupés had a 1.2, also used in the Berlina. In 1967 came the final and best known version, the 1.3 that was used till the last Fulvia in 1976. From 1969 onwards the rare 1.6 engine was also available in the Coupé and Sport.