The 15 superseeded the eleven in 1958 and was a further evolutionary step forward.

The 15 was available with either a 1500cc or 2000cc Coventry Climax engine, both of which were entered for the Le Mans 24hrs in 1958.

The 15 and then the unsuccessful 17 signalled the end of the Sports racing series as Lotus moved into the production road car market with the elite.

15 production ran until 1960.