The Lotus 100T was a Formula One car designed by Gérard Ducarouge and Martin Ogilvie for Team Lotus, used during the 1988 Formula One season. The 100T was an update of the previous Lotus 99T model; the car technically was virtually unchanged, except for a redesigned nose section and rear bodywork. The car was powered by the same 1.5L turbocharged Honda V6 engine that powered the McLaren team to 15 wins in 16 races in 1988.

In common with its progenitor model, the 100T was fitted with electronic active suspension, still an advanced system despite having been introduced the previous year. However, with the loss of Ayrton Senna to McLaren, and despite signing three-time and current World Champion Nelson Piquet, Lotus were very much an also-ran team during much of 1988. Piquet picked up a number of points, including three third-placed finishes, during the season, but the car's lack of ultimate speed resulted in Lotus's first season without a win or pole position since 1981.

At the end of the 1988 season turbocharged engines were outlawed, rendering the 100T chassis obsolete. It was replaced by the conventionally aspirated Lotus 101 for the 1989 Formula One season.

During the 1988 season, former World Champion Jackie Stewart test drove the 100T at the Snetterton Circuit which was Lotus's test track at the time. Within a few short laps he identified the car's basic problems. He said that the car lacked rigidity despite its carbon fibre and kevlar monocoque and that the chassis couldn't handle the abrupt power delivery of the turbocharged Honda engine which made the car difficult to drive, a complaint of Piquet, Nakajima and the teams test driver Martin Donnelly. He also noted how cramped the driving position was and that the steering wheel and instrument panel were so close together that it made the panel almost unreadable. He also said that "It was not a car that Nelson Piquet would have wanted to drive too many more times" and rated the car as "Perhaps one of the more disappointing cars I drove"