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

Little was changed between the 2002 and 2003 schedules; the Grand Prix of Washington, D.C., and Mid-Ohio Sports Car Course did not return, but both were instead replaced by the return of the Grand Prix of Atlanta at Road Atlanta. The Grand Prix of Mexico was originally scheduled for April 6 at the Autodromo Hermanos Rodriguez but was canceled due to financial issues.^[1]

Season results

Overall winner in bold.

Rnd	Circuit	LMP900 Winning Team	LMP675 Winning Team	GTS Winning Team	GT Winning Team	Results
		LMP900 Winning Drivers	LMP675 Winning Drivers	GTS Winning Drivers	GT Winning Drivers
1	Sebring	#1 Infineon Team Joest	#20 Dyson Racing	#3 Corvette Racing	#23 Alex Job Racing	Results
		Frank Biela Marco Werner Philipp Peter	Didier de Radiguès Chad Block Chris Dyson	Ron Fellows Johnny O'Connell Franck Fréon	Sascha Maassen Lucas Luhr
2	Road Atlanta	#38 ADT Champion Racing	#37 Intersport Racing	#4 Corvette Racing	#24 Alex Job Racing	Results
		JJ Lehto Johnny Herbert	Duncan Dayton Jon Field	Kelly Collins Oliver Gavin	Jörg Bergmeister Timo Bernhard
3	Sonoma	#1 Infineon Team Joest	#16 Dyson Racing	#3 Corvette Racing	#23 Alex Job Racing	Results
		Frank Biela Marco Werner	Butch Leitzinger James Weaver	Ron Fellows Johnny O'Connell	Sascha Maassen Lucas Luhr
4	Trois-Rivières	#1 Infineon Team Joest	#37 Intersport Racing	#4 Corvette Racing	#23 Alex Job Racing	Results
		Frank Biela Marco Werner	Jon Field Duncan Dayton	Kelly Collins Oliver Gavin	Sascha Maassen Lucas Luhr
5	Mosport	#1 Infineon Team Joest	#20 Dyson Racing	#3 Corvette Racing	#24 Alex Job Racing	Results
		Frank Biela Marco Werner	Andy Wallace Chris Dyson	Ron Fellows Johnny O'Connell	Jörg Bergmeister Timo Bernhard
6	Road America	#38 ADT Champion Racing	#20 Dyson Racing	#80 Prodrive	#31 Petersen/White Lightning	Results
		JJ Lehto Johnny Herbert	Andy Wallace Chris Dyson	Jan Magnussen David Brabham	Craig Stanton Johnny Mowlem
7	Laguna Seca	#1 Infineon Team Joest	#16 Dyson Racing	#80 Prodrive	#23 Alex Job Racing	Results
		Frank Biela Marco Werner	Butch Leitzinger James Weaver	Jan Magnussen David Brabham	Sascha Maassen Lucas Luhr
8	Miami	#38 ADT Champion Racing	#20 Dyson Racing	#80 Prodrive	#23 Alex Job Racing	Results
		JJ Lehto Johnny Herbert	Andy Wallace Chris Dyson	Darren Turner David Brabham	Sascha Maassen Lucas Luhr
9	Road Atlanta	#38 ADT Champion Racing	#37 Intersport Racing	#88 Prodrive	#24 Alex Job Racing	Results
		JJ Lehto Johnny Herbert	Jon Field Duncan Dayton Larry Connor	Alain Menu Tomáš Enge Peter Kox	Jörg Bergmeister Timo Bernhard Romain Dumas
Source:[4]

Teams Championship

Points are awarded to the top 10 finishers in the following order:^[5]

• 20-16-13-10-8-6-4-3-2-1

Exceptions being for the 12 Hours of Sebring and Petit Le Mans which award the top 10 finishers in the following order:^[5]

• 26-22-19-16-14-12-10-9-8-7

Cars failing to complete 70% of the winner's distance are not awarded points. Teams only score the points of their highest finishing entry in each race.

LMP900 Standings

Pos	Team	Chassis	Engine	Rd 1	Rd 2	Rd 3	Rd 4	Rd 5	Rd 6	Rd 7	Rd 8	Rd 9	Total
1	Infineon Team Joest	Audi R8	Audi 3.6L Turbo V8	26	16	20	20	20	13	20	16	19	170
2	ADT Champion Racing	Audi R8	Audi 3.6L Turbo V8	22	20	16	16	10	20	13	20	26	163
3	JML Team Panoz	Panoz LMP01 Evo	Élan 6L8 6.0L V8	14	10	10	13	16	16	16	13	22	130
4	American Spirit Racing	Riley & Scott Mk III C	Lincoln 5.0L V8	8	6		8		6	10	8	14	60
5	Intersport Racing	Lola B2K/10 Riley & Scott Mk III C	Judd GV4 4.0L V10 Élan 6L8 6.0L V8		8	6	6		8	8	10		46
6	Doran Lista Racing	Dallara SP1	Judd GV5 5.0L V10	10	13	13							36
7	Team Bentley	Bentley Speed 8	Bentley 4.0L Turbo V8	19									19
8	Audi Sport UK	Audi R8	Audi 3.6L Turbo V8	12									12
9	Taurus Sports Racing	Lola B2K/10	Judd GV4 4.0L V10	7									7

LMP675 Standings

Pos	Team	Chassis	Engine	Rd 1	Rd 2	Rd 3	Rd 4	Rd 5	Rd 6	Rd 7	Rd 8	Rd 9	Total
1	Dyson Racing Team	MG-Lola EX257	MG (AER) XP20 2.0L Turbo I4	26	16	20		20	20	20	20	22	164
2	Intersport Racing	MG-Lola EX257 Lola B01/60	MG (AER) XP20 2.0L Turbo I4 Judd KV675 3.4L V8	22	20		20		10	13	10	26	121
3	Essex Racing	Lola B2K/40	Nissan (AER) VQL 3.0L V6		8	13	16	10	16	16	13	16	108
4	Downing-Atlanta Inc.	WR LMP-02	Mazda 2.6L 4-Rotor		10				13			19	42
5	Jeff Bucknum Racing	Pilbeam MP91	Willman 6 3.4L V6					16	8				24

GTS Standings

Pos	Team	Chassis	Engine	Rd 1	Rd 2	Rd 3	Rd 4	Rd 5	Rd 6	Rd 7	Rd 8	Rd 9	Total
1	Corvette Racing	Chevrolet Corvette C5-R	Chevrolet 7.0L V8	26	20	20	20	20	16	16	10	19	167
2	Prodrive	Ferrari 550-GTS Maranello	Ferrari 6.0L V12	22	16	13	10	16	20	20	20	26	163
3	Team Olive Garden	Ferrari 550 Maranello	Ferrari 6.0L V12		8	8	13	10	10	10	13		72
4	Carsport America	Dodge Viper GTS-R Pagani Zonda GR	Dodge 8.0L V10 Mercedes-AMG 6.3L V12	16		6		8	4	8			42
5	Konrad Motorsport	Saleen S7-R	Ford 7.0L V8						6				6

GT Standings

Pos	Team	Chassis	Engine	Rd 1	Rd 2	Rd 3	Rd 4	Rd 5	Rd 6	Rd 7	Rd 8	Rd 9	Total
1	Alex Job Racing	Porsche 911 GT3-RS	Porsche 3.6L Flat-6	26	20	20	20	20	10	20	20	26	182
2	Risi Competizione	Ferrari 360GT Modena	Ferrari 3.6L V8			13	16	16		16	16	19	96
3	The Racer's Group	Porsche 911 GT3-RS	Porsche 3.6L Flat-6	12	13	10		2	16	8	2	16	79
4	Petersen/White Lightning	Porsche 911 GT3-RS	Porsche 3.6L Flat-6	22		8			20	13	10		73
5	J-3 Racing	Porsche 911 GT3-RS	Porsche 3.6L Flat-6		10	6	13	6	2			14	51
6	P.K. Sport	Porsche 911 GT3-RS	Porsche 3.6L Flat-6		6			8	1	10	13	9	47
7	ACEMCO Motorsports	Ferrari 360GT Modena	Ferrari 3.6L V8		8		10	3	3	4	3	10	41
8	Orbit Racing	Porsche 911 GT3-RS	Porsche 3.6L Flat-6	8	2	4	4	13			1	8	40
9	JMB Racing USA	Ferrari 360GT Modena	Ferrari 3.6L V8	16	3			1		6	8		34
10	ZIP Racing	Porsche 911 GT3-RS	Porsche 3.6L Flat-6	7			8		13		4		32
11	Seikel Motorsport	Porsche 911 GT3-RS	Porsche 3.6L Flat-6	19					6				25
12	Yokohama Advan	BMW M3 GTR	BMW 3.2L I6									12	12
13	DeWALT Racesport Salisbury	TVR Tuscan T400R	TVR Speed Six 4.0L I6	10									10
14	Inline Cunningham Racing	Porsche 911 GT3-RS	Porsche 3.6L Flat-6			1	6						7
15	Ferri Competizione	Ferrari 360GT Modena	Ferrari 3.6L V8					4					4