The 2003 American Le Mans Series season was the fifth season for the IMSA American Le Mans Series, and the 33rd overall season of the IMSA GT Championship. It was a series for Le Mans Prototypes (LMP) and Grand Touring (GT) race cars divided into 4 classes: LMP900, LMP675, GTS, and GT. It began March 15, 2003, and ended October 18, 2003, after nine races.

Dyson Racing's overall win at Sonoma Raceway was the first time in ALMS history that the overall win was captured by a vehicle not from the LMP900 class.

Schedule Rnd RaceLength CircuitLocation Date 1 Mobil 1 12 Hours of Sebring12 Hours Sebring International RacewaySebring, Florida March 15 2 Chevy Grand Prix of Atlanta2 Hours 45 Minutes Road AtlantaBraselton, Georgia June 29 3 Infineon Grand Prix of Sonoma2 Hours 45 Minutes Sonoma RacewaySonoma, California July 27 4 Le Grand Prix de Trois-Rivières3 Hours Circuit Trois-RivièresTrois-Rivières, Quebec August 3 5 Toronto Grand Prix of Mosport2 Hours 45 Minutes MosportBowmanville, Ontario August 17 6 Road America 5002 Hours 45 Minutes Road AmericaElkhart Lake, Wisconsin August 24 7 Fry's Electronics Sports Car Championships2 Hours 45 Minutes Mazda Raceway Laguna SecaMonterey, California September 7 8 Grand Prix Americas2 Hours 45 Minutes Bayfront ParkDowntown, Miami, Florida September 27 9 Petit Le Mans1000 Miles or 10 Hours Road AtlantaBraselton, Georgia October 18Sources: Races that were planned but later cancelled. +RaceLengthCircuitLocationDateCancellation reason Mexico City6 HoursAutódromo Hermanos RodríguezMexico CityApril 5Financial issues European eventN/AN/AEuropeLate MayNo viable candidate Grand Prix of Washington, D.C.2 Hours 45 MinutesRFK Stadium street circuitWashington, D.C.June 29Operational problems

Schedule changes The ALMS originally announced an 11-round schedule with the highlights being planned races in Europe and Mexico. The planned European round was to be at a premier European facility in mid to late May, between the time of the traditional pre-practice for the 24 Hours of Le Mans and the actual running of the Le Mans 24-hour race in mid-June. The European round would be dropped as no viable candidates could be found as "The combination of many European tracks experiencing serious financial challenges, coupled with the general state of European sports car racing has prevented us from confirming an acceptable arrangement for the American Le Mans Series and its participants."

Just before the season began, the ALMS announced that the races in Mexico and Washington, DC had both been cancelled due to ongoing problems with the race organizers. the Grand Prix of Atlanta returned for the first time since 1999 to replace the cancelled events.

Road America was reduced from 500 miles to 2 hours and 45 minutes to bring in line with the rest of the schedule, and Mid-Ohio Sports Car Course did not return for 2003. Entry list Le Mans Prototype 900 (LMP900) TeamChassisEngineTyreNo.DriversRnds. Team NasamaxReynard 01QCosworth XDE 2.7 L Turbo V8 (Bio-ethanol)01 Bryan Herta1 Robbie Stirling1 Romain Dumas1 Infineon Team JoestAudi R8Audi 3.6 L Turbo V81 Frank BielaAll Marco WernerAll Philipp Peter1 Lister Storm RacingLister Storm LMPChevrolet LS1 6.0 L V86 Jamie Campbell-Walter1 Ian MacKellar1 Team BentleyBentley Speed 8Bentley 4.0 L Turbo V87 Tom Kristensen1 Guy Smith1 Rinaldo Capello18 Johnny Herbert1 David Brabham1 Mark Blundell1 Audi Sport UKAudi R8Audi 3.6 L Turbo V89 Mika Salo1 Jonny Kane1 Perry McCarthy1 JML Team PanozPanoz LMP01 EvoÉlan 6L8 6.0L V810 Olivier BerettaAll Max Papis1–2, 9 Gunnar Jeannette1, 3 David Saelens4–911 Scott Maxwell1, 4–5, 8–9 Benjamin Leuenberger1, 3, 6–7, 9 John Graham1 David Saelens2–3 Gunnar Jeannette2, 4–9 American Spirit RacingRiley & Scott Mk III CLincoln (Élan) 5.0 L V812 Michael LewisAll Tomy DrissiAll Guy Cosmo1 Melanie Paterson9 Doran Lista RacingDallara SP1Judd GV4 4.0 L V1027 Didier Theys1–3 Eric van de Poele1–2 Fredy Lienhard1 Bill Auberlen3 Intersport RacingLola B2K/10BJudd GV4 4.0 L V1030 Clint FieldAll Rick Sutherland1, 3, 6–7 John Macaluso1 Mike Durand2, 4, 8–9 Georges Forgeois5 Larry Oberto9 Jim Matthews RacingRiley & Scott Mk III CFord (Yates) 6.0 L V836 Jim Matthews1 Marc Goossens1 Jan Magnussen1 Champion RacingAudi R8Audi 3.6 L Turbo V838 J.J. LehtoAll Stefan Johansson1, 9* Emanuele Pirro1 Johnny Herbert2–9 Taurus Sports RacingLola B2K/10BJudd GV4 4.0 L V1077 Phil Andrews1 Justin Keen1 Larry Oberto1 Sezio Florida Racing TeamNorma M2000Ford (Kinetic) 6.0 L V887 Allen Ziegelman1 Patrice Roussel1 Ian James1

Le Mans Prototype 675 (LMP675) TeamChassisEngineTyreNo.DriversRnds. RN MotorsportsDBA4 03SZytek ZG348 3.4 L V815 Hayanari Shimoda1 John Nielsen1 Dyson Racing TeamMG-Lola EX257MG (AER) XP20 2.0 L Turbo I416 James WeaverAll Butch LeitzingerAll Andy Wallace1, 920 Chris DysonAll Didier de Radiguès1, 9 Chad Block1, 9 Andy Wallace2–8 Marshall Cooke RacingLola B2K/40Ford (Millington) 2.0 L Turbo I418 Ben Devlin1 Jason Workman1 Melanie Paterson1 Essex RacingLola B2K/40Nissan (AER) VQL 3.0L V618 Jason Workman2–9 Melanie Paterson2, 4–5 David McEntee3 James Gue6 Scott Bradley7–9 Andrew Davis9 Intersport RacingMG-Lola EX257 (1-8) Lola B01/60 (9)MG (AER) XP20 2.0 L Turbo I4 (1-8) Judd KV675 3.4 L V8 (9)37 Jon FieldAll Duncan DaytonAll Mike Durand1 Larry Connor9 Team Bucknum RacingPilbeam MP91Willman (JPX) 3.4 L V656 Bryan WillmanAll Chris McMurryAll Jeff Bucknum1–8 Alan Rudolph9 Downing-Atlanta Inc.WR LMP02Mazda R26B 2.6L 4-Rotor64 Jim Downing2, 6, 9 Howard Katz2, 6, 9 Yojiro Terada9 AB MotorsportPilbeam MP84Nissan (AER) VQL 3.0L V677 Joe Blacker2 John Burke2

Grand Touring Sport (GTS) TeamChassisEngineTyreNo.DriversRnds. Team Olive GardenFerrari 550 MaranelloFerrari 6.0 L V120 Emanuele NaspettiAll Mimmo Schiattarella1–6, 8–9 Johnny Cecotto1 Bill Auberlen7 Joël Camathias9 ProdriveFerrari 550-GTS MaranelloFerrari 5.9L V1208 Jan Lammers9 Jérôme Policand9 Frédéric Dor980 Darren Turner1, 8 Anthony Davidson1, 9 Kelvin Burt1 Jérôme Policand2 Danica Patrick2 David Brabham3–9 Jan Magnussen3–7, 988 Tomáš EngeAll Peter KoxAll Jamie Davies1 Alain Menu9 Konrad MotorsportSaleen S7-RFord 7.0L V82 Franz Konrad1, 5–6, 8 Robert Nearn1, 8 Toni Seiler1 Mark Neuhaus5–6 Walter Lechner Jr.5 Wolfgang Kaufmann6 Corvette RacingChevrolet Corvette C5-RChevrolet 7.0 L V83 Ron FellowsAll Johnny O'ConnellAll Franck Fréon1, 94 Oliver GavinAll Kelly CollinsAll Andy Pilgrim1, 9 Carsport AmericaPagani Zonda GR (1) Dodge Viper GTS-R (6)Mercedes-AMG 6.3 L V12 (1) Dodge 8.0L V10 (6)17 Mike Hezemans1 Anthony Kumpen1 Tom Weickardt6 Joe Ellis6 Romeo Kapudija6Dodge Viper GTS-RDodge 8.0L V1071 Jean-Philippe Belloc1–3, 5–9 Tom Weickardt1–2, 5, 7–9 Jeff Altenburg1, 6 Aaron Povoledo3 Éric Cayrolle9 Graham Nash MotorsportSaleen S7-RFord 7.0L V883 Thomas Erdos1 Pedro Chaves1 Gavin Pickering1

Grand Touring (GT) TeamChassisEngineTyreNo.DriversRnds. Hyper SportPorsche 996 GT3-RS (1) Panoz Esperante GT-LM (2-9)Porsche 3.6 L Flat-6 (1) Ford (Elan) 5.0 L V8 (2-9)03 Brad Nyberg1–4, 7–9 Rick Skelton1–4, 7–9 Joe Foster1–4, 7, 9 RWS-Yukos MotorsportPorsche 996 GT3-RPorsche 3.6 L Flat-607 Walter Lechner, Jr.1 Stéphane Daoudi1 Nikolai Fomenko1 MCRChevrolet Corvette C5-RGTChevrolet LS1 7.0 L V8?5 Bob Mazzuoccola1* Shane Lewis1* Yokohama/ADVANBMW M3 E46BMW 3.2 L I66 Bill Auberlen9 Boris Said9 Hans-Joachim Stuck9 Perspective RacingPorsche 996 GT3-RSPorsche 3.6 L Flat-621 Thierry Perrier1* Angelo Barretto1* Michel Neugarten1* Alex Job RacingPorsche 996 GT3-RSPorsche 3.6 L Flat-623 Sascha MaassenAll Lucas LührAll24 Timo BernhardAll Jörg BergmeisterAll Romain Dumas9 JMB Racing USAFerrari 360 Modena N-GTFerrari 3.6 L V828 Stéphane GrégoireAll Christian Pescatori1, 4 Fabio Babini1 Eliseo Salazar2–3, 5, 7–8 Iradj Alexander5–7 Stephen Earle9 Philip Shearer929 Andrea Garbagnati1, 3 Ludovico Manfredi1, 3 Stephen Earle1, 7–8 Peter Kutemann5–6 Antoine Gosse5 Philip Shearer6 Mark Neuhaus7–8 White Lightning Petersen MotorsportsPorsche 996 GT3-RSPorsche 3.6 L Flat-631 Johnny Mowlem1, 3, 6–9 Craig Stanton1, 3, 6–9 Niclas Jönsson1 Michael Petersen9 Ferri CompetizioneFerrari 360 Modena GTFerrari 3.6 L V832 Andrea Bertolini5 Mauro Baldi5 ZIP RacingPorsche 996 GT3-RSPorsche 3.6 L Flat-633 Spencer Pumpelly1–4, 6–8 Andy Lally1–4, 6–8 Steven Ivankovich1 Romeo Kapudija839 Emil Assentato1 Nick Longhi1 Brent Sherman1 Risi CompetizioneFerrari 360 Modena GTFerrari 3.6 L V834 Marino Franchitti1 Kevin McGarrity1 Phillip Bennett135 Ralf KellenersAll Anthony LazzaroAll Terry Borcheller1 Alegra MotorsportsBMW M3 E46BMW 3.2 L I640 Boris Said1 Catersby Jones1 Carlos DeQuesada1 Bill Auberlen8 Niclas Jönsson841 Ross Bluestein8 Carlos DeQuesada8 DeWALT Racesport SalisburyTVR Tuscan T400RTVR Speed Six 4.0 L I641 Rob Barff1 Richard Hay1 Richard Stanton1 OrbitPorsche 996 GT3-RSPorsche 3.6 L Flat-642 Joe Policastro, Sr.1–3, 6–9 Joe Policastro, Jr.1–3, 6–9 Mike Fitzgerald1 Leo Hindery6 Randy Pobst943 Peter BaronAll Leo Hindery1-3, 7, 9 Marc Lieb1, 4–6, 8 Mike Rockenfeller9 Spyker SquadronSpyker C8 Double-12RBMW (Mader) 4.0 L V848 Norman Simon1 Hans Hugenholtz1 Patrick van Schoote1 Seikel MotorsportPorsche 996 GT3-RSPorsche 3.6 L Flat-652 Philip Collin1–2, 6, 9 John Lloyd1, 6 David Shep1, 5 Tony Burgess2, 5 Andrew Bagnall953 Alex Caffi1 Gabrio Rosa1 Andrea Chiesa1 P.K. SportPorsche 996 GT3-RPorsche 3.6 L Flat-660 Robin LiddellAll David Warnock1, 9 Piers Masarati1 Jean-Philippe Belloc2 Alex Davison3–4, 6 Vic Rice5 Alex Caffi7–961 Ian Donaldson1 Bart Hayden1 Gregor Fisken1 Vic Rice2–4, 6–7, 9 Piers Masarati2, 5–6 Keith Alexander3 Spencer Trenery4 John Graham5 David Warnock7–8 Ron Atapattu8 Romeo Kapudija9 Jon Groom9 ACEMCO MotorsportsFerrari 360 Modena GTFerrari 3.6 L V863 Shane LewisAll Andrew Davis1–2 B. J. Zacharias1 Terry Borcheller3–9 Darren Law9 The Racer's GroupPorsche 996 GT3-RSPorsche 3.6 L Flat-666 Kevin BucklerAll Jim Pace1 Eliseo Salazar1 Cort Wagner2–9 Patrick Long967 Michael Schrom1–7 Pierre Ehret1–3, 6–8 Vic Rice1 Marc Bunting2 Jean-Francois Dumoulin4 Jeffrey Pabst5 Jeff Zwart8–9 Tom Nastasi9 David Donner968 Marc BuntingAll Chris GleasonAll Cort Wagner1 Pierre Ehret9 T2M MotorsportPorsche 996 GT3-RPorsche 3.6 L Flat-678 Georges Forgeois1 Derek Clark1 Chip Vance1 J-3 RacingPorsche 996 GT3-RSPorsche 3.6 L Flat-679 David MurryAll Justin JacksonAll Brian Cunningham1, 9 Inline Cunningham RacingPorsche 996 GT3-RSPorsche 3.6 L Flat-689 Oswaldo Negri, Jr.3–4, 7, 9 Scott Bader3–4 Burt Frisselle7, 9 Spencer Pumpelly9* Vici RacingLamborghini Diablo GTRLamborghini 6.0 L V1290 Ronny Meixner1* Joseph Safina1* Cristiano Piquet1* * Was on the entry list but did not participate in the event. Season results Overall winner in bold.