The Honda RA099 was a prototype Formula One racecar, commissioned by Honda, designed by ex-Ferrari and Tyrrell designer Harvey Postlethwaite and built by Dallara in 1999. Its purpose was similar to the one surrounding the Toyota TF101 of 2001, in that it was supposed to be a working test car used in preparation for a full-scale assault on Grand Prix racing in the following year/s.

Honda Racing had last competed in Formula One as a constructor in the 1960s but had pulled out of the sport, after its driver Jo Schlesser was killed in one of its cars in the 1968 French Grand Prix at Rouen. The company had re-entered Formula One in 1983 as engine supplier to the Spirit team before moving on to have extremely successful partnerships with Williams (1984-1987) and McLaren (1988-1992) as well as less illustrious partnerships with Lotus (1987-1989) and Tyrrell (1991).

After leaving the sport as an engine supplier in 1992, the company worked with Mugen Motorsports to provide engines in F1 for the likes of Lotus, Prost (née Ligier) and Jordan but was not directly involved in Formula One itself.

In 1998, Honda were seriously considering a return to the sport as a constructor, and hired the respected designer Dr. Harvey Postlethwaite, out of work since the demise of Tyrrell that same year, to design a chassis. This he did, and the car, built by Italian company and former F1 constructor in their own right Dallara, tested at Jerez in the hands of Dutch driver Jos Verstappen with some success.

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