The 2005 Grand Prix of Sonoma was the fifth race for the 2005 American Le Mans Series season, held at Infineon Raceway. It took place on July 17, 2005. It was the last ALMS race held at Infineon. It was the final ALMS race held at Sonoma, the event being transferred to the Rolex Sports Car Series the following year.
Class winners in bold. Cars failing to complete 70% of winner's distance marked as Not Classified (NC).
| Pos | Class | No | Team | Drivers | Chassis | Tyre | Laps | |
|---|---|---|---|---|---|---|---|---|
| Engine | ||||||||
| 1 | LMP1 | 2 |  ADT Champion Racing |  Frank Biela Emanuele Pirro | Audi R8 | 111 | ||
| Audi 3.6L Turbo V8 | ||||||||
| 2 | LMP1 | 20 | Dyson Racing | Chris Dyson Andy Wallace | MG-Lola EX257 | 111 | ||
| MG (AER) XP20 2.0L Turbo I4 | ||||||||
| 3 | LMP1 | 1 | ADT Champion Racing | Marco Werner JJ Lehto | Audi R8 | 110 | ||
| Audi 3.6L Turbo V8 | ||||||||
| 4 | LMP2 | 37 | Intersport Racing | Clint Field Liz Halliday | Lola B05/40 | 105 | ||
| AER P07 2.0L Turbo I4 | ||||||||
| 5 | LMP1 | 16 | Dyson Racing | Butch Leitzinger James Weaver | MG-Lola EX257 | 105 | ||
| MG (AER) XP20 2.0L Turbo I4 | ||||||||
| 6 | LMP2 | 10 | Miracle Motorsports | Jeff Bucknum Chris McMurry | Courage C65 | 105 | ||
| AER P07 2.0L Turbo I4 | ||||||||
| 7 | GT1 | 3 | Corvette Racing |  Ron Fellows Johnny O'Connell | Chevrolet Corvette C6.R | 104 | ||
| Chevrolet 7.0L V8 | ||||||||
| 8 | GT1 | 4 | Corvette Racing | Oliver Gavin Olivier Beretta | Chevrolet Corvette C6.R | 104 | ||
| Chevrolet 7.0L V8 | ||||||||
| 9 | GT1 | 63 | ACEMCO Motorsports | Terry Borcheller Johnny Mowlem | Saleen S7-R | 104 | ||
| Ford 7.0L V8 | ||||||||
| 10 | LMP2 | 8 | B-K Motorsport | Guy Cosmo James Bach | Courage C65 | 102 | ||
| Mazda R20B 2.0L 3-Rotor | ||||||||
| 11 | GT1 | 35 | Maserati Corse Risi Competizione | Andrea Bertolini Fabrizio de Simone | Maserati MC12 | 102 | ||
| Maserati 6.0L V12 | ||||||||
| 12 | GT2 | 23 | Alex Job Racing | Timo Bernhard Romain Dumas | Porsche 911 GT3-RSR | 100 | ||
| Porsche 3.6L Flat-6 | ||||||||
| 13 | GT2 | 31 | Petersen Motorsports White Lightning Racing | Jörg Bergmeister Patrick Long | Porsche 911 GT3-RSR | 99 | ||
| Porsche 3.6L Flat-6 | ||||||||
| 14 | GT2 | 43 | BAM | Mike Rockenfeller Wolf Henzler | Porsche 911 GT3-RSR | 99 | ||
| Porsche 3.6L Flat-6 | ||||||||
| 15 | GT2 | 45 | Flying Lizard Motorsports | Johannes van Overbeek Jon Fogarty | Porsche 911 GT3-RSR | 98 | ||
| Porsche 3.6L Flat-6 | ||||||||
| 16 | GT2 | 50 | Panoz Motor Sports | Bill Auberlen Robin Liddell | Panoz Esperante GT-LM | 98 | ||
| Ford (Elan) 5.0L V8 | ||||||||
| 17 | GT2 | 79 | J3 Racing | Justin Jackson Tim Sugden | Porsche 911 GT3-RSR | 97 | ||
| Porsche 3.6L Flat-6 | ||||||||
| 18 | GT2 | 44 | Flying Lizard Motorsports | Lonnie Pechnik Seth Neiman | Porsche 911 GT3-RSR | 96 | ||
| Porsche 3.6L Flat-6 | ||||||||
| 19 | GT2 | 24 | Alex Job Racing | Ian Baas Randy Pobst | Porsche 911 GT3-RSR | 96 | ||
| Porsche 3.6L Flat-6 | ||||||||
| 20 DNF | GT1 | 71 | Carsport America | Michele Rumolo Tom Weickardt | Dodge Viper GTS-R | 80 | ||
| Dodge 8.0L V10 | ||||||||
| 21 DNF | GT1 | 5 | Pacific Coast Motorsports | Alex Figge Ryan Dalziel | Chevrolet Corvette C5-R | 78 | ||
| Chevrolet 7.0L V8 | ||||||||
| 22 DNF | GT2 | 78 | J3 Racing | Pierre Ehret David Murry | Porsche 911 GT3-RSR | 47 | ||
| Porsche 3.6L Flat-6 | ||||||||
| 23 DNF | GT2 | 51 | Panoz Motor Sports | Bryan Sellers Marino Franchitti | Panoz Esperante GT-LM | 39 | ||
| Ford (Elan) 5.0L V8 | ||||||||
| 24 DNF | LMP1 | 12 | Autocon Motorsports | Bryan Willman Michael Lewis | Riley & Scott Mk III C | 5 | ||
| Elan 6L8 6.0L V8 |