John Leffler is a former Australian racing driver. Leffler is best known for driving open-wheelers and winning the Australian Drivers' Championship in 1976.
In the early 1970s he turned his hand to Formula Ford racing a Bowin P6F in which he won the 1973 TAA Formula Ford Driver to Europe Series. In 1974 he contested the Australian Formula 2 Championship and finished third.
In 1975 Leffler stepped up to the Australian Drivers' Championship (the "Gold Star") and driving a Bowin P8 Chevrolet finished fifth in the series. The following year he secured the 1976 Australian Drivers' Championship title in a Lola T400 with a string of consistent placings but without actually winning a round.
Leffler also co-drove for some of the leading Australian touring car drivers in endurance events. He co-drove with Bob Morris at the 1974 Sandown 250 finishing second in a Ron Hodgson Motors Holden Torana GTR XU-1 and at the 1978 Bathurst 1000 he came second with Allan Grice in a Craven Mild Racing Holden LX Torana SS A9X Hatchback.
- Racing Car News Championship Year No.1, page 61
- Evan Green, Evan Green’s World of Motor Sport, 1977, page 18
- Jim Shepherd, A History of Australian Motor Sport, pages 55 to 57
- Official Programme, Adelaide International Raceway, Sunday, 8 Feb 1976, page 35
- Official Programme, Adelaide International Raceway, Sunday, 27 February 1977, page 41
- Australian Competition Yearbook 1974 - pages 59, 75, 208
- Australian Competition Yearbook 1975 - pages 46, 70
- Australian Competition Yearbook 1976 - pages 65, 108, 117-120, 188
- Australian Competition Yearbook 1977 - pages 104-110
- Australian Competition Yearbook 1978 - page 115