The 1986 FIA Formula One World Championship was the 40th season of FIA Formula One motor racing. It featured the 1986 Formula One World Championship for Drivers and the 1986 Formula One World Championship for Manufacturers, both of which commenced on 23 March and ended on 26 October after sixteen races. The Drivers' Championship was won by Alain Prost, Prost was the first driver to win back-to-back Drivers' Championships since Jack Brabham in 1959 and 1960. Together with Prost, Nigel Mansell, Nelson Piquet and Ayrton Senna dominated throughout the season and formed what was dubbed as the "Gang of Four". The 1986 season also marked the final Formula One season of 1982 Drivers' Champion Keke Rosberg who retired from the sport at the end of season following a difficult season with McLaren.

After 1986, Renault left the sport as an engine supplier due to company restructuring, only to return in 1989. The Constructors' Championship was won by Williams-Honda. Honda became the first Japanese engine supplier to win a Constructors' Championship.

The following competitors contested the 1986 Formula One World Championship.

An early version of the calendar showed 20 races. These rounds were eventually removed:

Back in 1980, Renault proved that turbocharged engines were the way to success and by the half-way point in the 1985 season, all teams had followed their example. The FIA saw that the power output from turbo engines had doubled in the past six years. The 1986 F1 cars in qualifying trim proved to be the most powerful Grand Prix cars in history. Manufacturers mentioned numbers above 1,400 bhp (1,000 kW), powering cars that weighed just 540 kg (1,190 lb) giving a staggering power-to-weight ratio of 2,500 hp/ton. This power output was only seen in qualifying trim, since the specially prepared engines, tyres and gearboxes could only hold on for two to four laps under this immense force before destroying themselves, and in race trim, with the engines limited in power to conserve them to run a 190-mile (306 km) race distance, the cars were not much slower.

So after mandating turbocharged engines for 1986, the governing body decided to re-allow naturally aspirated engines for 1987, and at the same time started reining in the power of turbo engines, before banning them altogether for the 1989 season.

In Sky TV's "Tales from the crypt" Mansell said that at the end of year FIA Paris prizegiving, Bertie Martin, the Clerk of the Course at Adelaide, told him that had he hit the wall and debris covered the track, he would have red-flagged the race and, as two thirds race distance had been completed, Mansell would have been world champion.^{[citation needed]}

The 1986 Formula One World Championship was contested over a sixteen-race series.