The Osella FA1B was a Formula 1 racing car developed by the Italian Formula 1 team Osella Squadra Corse and used for six different drivers in the 1980 and 1981 World Championships. It replaced the Osella FA1. With him, the team did not score any world championship points.

Since the very heavy F1A could only be modified to a limited extent, the team management decided in April 1980 to develop a completely new car. It was designed by Enzo Osella and Giorgio Valentini, who had designed the short-lived Merzario A3 for Team Merzario a year earlier.

The FA1B was basically the same as the previous model. The suspension has been slightly reworked. 

As with the FA1, the monocoque of the new vehicle was essentially made of aluminum. However, it was much narrower than that of the FA1. This allowed the surfaces of the sidepods to be widened, which led to an improved effect of the ground effect. 

Osella claimed that the FA1B developed five percent more downforce than the FA1.  The FA1B was also significantly lighter than its predecessor. In many cases, the weight of the FA1B is given as 600 kg. This would have exceeded the minimum weight specified by the regulations by only 5 kg. In the literature, however, there are doubts about the correctness of this value. 

A Cosworth DFV eight-cylinder engine continued to serve as propulsion; the power was transmitted via a Hewland gearbox.

A total of four FA1B vehicles were built. In 1980, a single car (FA1B/1) was built, and in 1981 Osella designed three more examples (FA1B/2, FA1B/3 and FA1B/4). The FA1B/1 was only used in 1980. In 1981, the FA1B/3 and FA1B/4 chassis were launched, but no racing appearances are recorded for the FA1B/2. 

The Osella FA1G was a Formula 1 racing car produced by the Italian racing team Osella Squadra Corse, which was entered by five drivers for more than 30 races in 1985, 1986 and 1987 and finished seven times.

It was a further development of the Osella FA1F introduced in 1984 and, like the latter, was closely related to the Alfa Romeo 183T. Together with the FA1F, it significantly shaped Osella's image in the turbo era.

The Osella FA1G used the same monocoque construction and overall technical layout as the FA1F. It differed from its predecessor primarily in a series of technical modifications developed by Giuseppe Petrotta for Osella. All this work was based on Petrotta's intuition; Wind tunnel tests were not carried out with the FA1G for cost reasons.

The weight of the car was given as 575 to 580 kg. This made it 35 kg more than the lightest Formula 1 cars of the 1985 season.

Like its predecessor, the FA1G used the 1.5-liter eight-cylinder turbocharged engine from Alfa Romeo (Tipo 890T). Initially, they were still at the level of development of 1983. It was not until 1987 – two years after their debut in the now defunct Alfa factory team – that the engines with fully electronic Bosch injection were finally available for Osella. 

In the 1985 season, Osella fielded only one car. The team's sole driver until the British Grand Prix was Piercarlo Ghinzani; then the Dutchman Huub Rothengatter rode for Osella. The FA1G made its debut at the San Marino Grand Prix in May.

The team produced two examples of the FA1G that failed to score any world championship points.