This list of 2003 motorsport champions is a list of national or international auto racing series with a Championship decided by the points or positions earned by a driver from multiple races.
| Series | Driver | Season article |
|---|---|---|
| American Le Mans Series | LMP900:  Frank BielaLMP900: Marco Werner | 2003 American Le Mans Series season |
LMP675:  Chris Dyson | ||
GTS:  Ron FellowsGTS: Johnny O'Connell | ||
| GT: Lucas Luhr GT: Sascha Maassen | ||
| Rolex Sports Car Series | DP: Terry Borcheller | 2003 Rolex Sports Car Series season |
| SRPII: Steve Marshall | ||
| GTS: Tommy Riggins GTS: Dave Machavern | ||
| GT: Cort Wagner GT: Brent Martini | ||
| FIA Sportscar Championship | SR1:  Jan LammersSR1: John Bosch | 2003 FIA Sportscar Championship season |
| SR1 Teams: Racing for Holland | ||
SR2:  Mirko SavoldiSR2: Piergiuseppe Peroni | ||
| SR2 Teams: Lucchini Engineering | ||
| FIA GT Championship | GT: Thomas Biagi GT: Matteo Bobbi | 2003 FIA GT Championship season |
| GT Teams: BMS Scuderia Italia | ||
N-GT:  Stéphane OrtelliN-GT: Marc Lieb | ||
| N-GT Teams: Freisinger Motorsport |
| Series | Driver | Season article | |
|---|---|---|---|
| European Touring Car Championship | Overall: Gabriele Tarquini | ||
| Manufacturers: BMW | |||
| Independents: Duncan Huisman | |||
| V8 Supercars |  Marcos Ambrose | 2003 V8 Supercar Championship Series |
| Series | Driver/Co-Driver | Season article |
|---|---|---|
| World Rally Championship |  Petter Solberg Phil Mills | 2003 World Rally Championship season |
| Manufacturer: Citroën | ||
| Junior World Rally Championship | Brice Tirabassi | |
| Production World Rally Championship | Martin Rowe |
