The Lotus 97T was a Formula One racing car that competed in the 1985 season, and was a development of the Lotus 95T, taking into account new requirements for Formula One rear wings. It was designed by French designer Gerard Ducarouge and used a turbocharged engine from Renault. Aerodynamic elements from the Lotus 96T, which was designed for IndyCar but never raced, were used in the development of this model.

In 1985, Lotus signed rising star Ayrton Senna from Toleman to join the experienced Elio de Angelis. De Angelis had finished third in the 1984 World Championship and looked very good behind the wheel of the Lotus 95T

The 97T proved to be very competitive in the 1985 season. The team's drivers won three stages and eight pole positions, which allowed Lotus to take fourth place in the Constructors' Championship. Senna brought the team's first victory of the 1985 season: starting from pole at the Portuguese Grand Prix in the pouring rain, he beat his pursuers by more than a minute. The Brazilian won again, at Spa, and de Angelis brought another victory at Imola, after Prost was disqualified.

The car was fast but unreliable, and frequent retirements in races prevented Lotus drivers from fighting for higher places in both categories.

This car marked the beginning of the team's renaissance, which continued in the 1986 and 1987 seasons, when the 97T was replaced by the Lotus 98T and Lotus 99T