The 1991 NASCAR Winston Cup Series was the 43rd of professional stock car racing in the United States and the 20th modern-era Cup Season. It began February 10 and ended November 17. Dale Earnhardt of Richard Childress Racing won his fifth Winston Cup championship at the conclusion of the season. The season was marred by the death of driver and team owner J. D. McDuffie, who was killed in a wreck at Watkins Glen.

A bevy of new Pit rules were introduced at Daytona to start out the 1991 season, in response to the death of a Melling Racing rear tire changer in a pit road accident at Atlanta the previous November. The new rules changed the complexity of the races, and over the course of the season, they would be tweaked and revised. By mid-season, most of the more complicated rules were scrapped, but a few were made permanent. The pit road speed limit (at all times) and use of the "lollipop" style signboard were the significant changes made permanent (and remain to this day).

The 1991 season introduced the past champion's provisional (also known as the "Petty rule"), which allowed a former Cup Series champion to claim the final starting position in a race if he failed to qualify on speed, and if he was too low in the points standings to secure an ordinary provisional spot. If there were two or more former champions that failed to qualify, the Champion's Provisional would be awarded to the most recent champion. This rule was implemented after Richard Petty failed to qualify for four races in 1989, resulting in a drop in ratings that season.

The 1991 season was also the final year for Buick as a full-time manufacturer in the series; Buick cars would run only limited schedules in 1992 and 1993 before leaving the series for good.

The Nashville Network debuted as a cable television partner with the Cup Series in 1991. For 1991, there were five television networks broadcasting the 29-race Winston Cup Series schedule: CBS, ABC, ESPN, TBS, and TNN.

1991 NASCAR Winston Cup Series Drivers

Full-time teams ManufacturerTeamDriverCrew chief Buick Bobby Allison Motorsports 12 Hut Stricklin Jimmy Fennig King Racing 26 Brett BodineStavola Brothers Racing 8 Rick Wilson Harry HydeChevrolet Darrell Waltrip Motorsports 17 Darrell Waltrip Jeff Hammond Hendrick Motorsports 5 Ricky Rudd Waddell Wilson 25 Ken Schrader Richard Broome Marcis Auto Racing 71 Dave Marcis Bob Marcis Morgan-McClure Motorsports 4 Ernie Irvan Tony Glover Richard Childress Racing 3 Dale Earnhardt Kirk Shelmerdine Travis Carter Enterprises 98 Jimmy Spencer Travis Carter Bob Whitcomb Racing 10 Derrike Cope Buddy ParrottFord AK Racing 7 Alan Kulwicki Paul Andrews Bud Moore Engineering 15 Morgan Shepherd Donnie Wingo Junior Johnson & Associates Geoff Bodine Tim Brewer Tommy Ellis 22 Sterling Marlin Mike Beam Little Racing 19 Chad LittleHarry Hyde Melling Racing 9 Bill Elliott Ernie ElliottRobert Yates Racing 28 Davey Allison Larry McReynoldsRoush Racing 6 Mark Martin Robin Pemberton U.S. Racing 55 Ted Musgrave (R) Wood Brothers Racing 21 Dale Jarrett Eddie WoodOldsmobile Hagan Racing 94 Terry Labonte Steve Lloyd Leo Jackson Motorsports 33 Harry Gant Andy Petree Precision Products Racing 1 Rick Mast Pontiac Bahari Racing 30 Michael Waltrip Bill IngleCale Yarborough Motorsports66 Dick Trickle Lake Speed Chuck Bown Dorsey Schroeder Randy LaJoie Penske Racing 2 Rusty Wallace Jimmy Makar Petty Enterprises 43 Richard Petty Robbie LoomisSABCO Racing42 Kyle Petty Gary NelsonKenny Wallace Tommy Kendall Bobby Hillin Jr. Team III Racing24 Mickey Gibbs Barry Dodson Dick Trickle Dorsey Schroeder Kenny Wallace Jimmy Hensley Oldsmobile Chevrolet RahMoc Enterprises 75 Joe Ruttman Bob Rahilly Oldsmobile Pontiac Tri-Star Motorsports 68 Bobby Hamilton (R) Pontiac Oldsmobile Means Racing52 Jimmy Means Bobby Hillin Jr. Mike Wallace

Part-time teams ManufacturerTeamDriverCrew chiefRoundsBuickAAG Racing34 Gary Balough Dick Trickle Hylton Motorsports 48 James Hylton Labonte Motorsports 44 Jack Sellers Linro Motorsports13 Brian Ross Kerry Teague Randy LaJoie Gary Balough Oma Kimbrough 29 Kerry Teague BS&S Motorsports49Stanley Smith (R) Chevrolet A. J. Foyt Enterprises 14 Mike Chase Bahre Racing65Dave Mader III Mader Racing Ball Motorsports 99 Brad Teague Buck Baker Racing 87 Randy Baker Daytona Speed, Inc. 18 Greg Sacks Faggart Racing 76 Robbie Faggart Hylton Motorsports 48 James Hylton Italian Connection 96 Phil Parsons Larry Hedrick Motorsports 41 Larry Pearson O'Neil Racing 63 Norm Benning Phoenix Racing 51 Jeff Purvis Pinnacle Racing 86 Jeff Green Ross Racing 58 Brian Ross Sadler Brothers Racing95 Rick Jeffrey Kerry Teague Eddie Bierschwale Spears Motorsports 76 Bill Sedgwick Team Ireland53 John Paul Jr. Bobby Hillin Jr. S&H Racing80Jimmy Horton Ford Compton Racing 69 Dorsey Schroeder Donlavey Racing90 Robby GordonJunie Donlavey Wally Dallenbach Jr. (R) Steve Perry Freymiller Racing 23 Mike Chase Ragan Racing 77 Ken Ragan Stahl Racing 82 Mark Stahl Waters Racing 0 Delma Cowart Oldsmobile Barkdoll Racing 73 Phil Barkdoll Bierschwale Motorsports 23 Eddie Bierschwale Close Racing47 Rich Bickle Greg Sacks A. J. Foyt Enterprises14 Mike Chase Labonte MotorsportsBobby Labonte 44 Irv Hoerr Moroso Racing20 Sammy Swindell Bobby Hillin Jr. Kim Campbell Buddy Baker Ricky Craven 27 Bobby Hillin Jr. 88 Buddy Baker Phoenix Racing 51 Jeff Purvis Sadler Brothers Racing 95 Kerry Teague Pontiac Bahre Racing 65 Dave Mader III Hill Motorsports 56 Jerry Hill Mansion Motorsports 27 Gary Balough Mark Gibson Racing 59 Mark Gibson McDuffie Racing 70 J. D. McDuffie Mueller Brothers Racing 89 Jim Sauter Osterlund Motorsports 88 Buddy Baker

Schedule No. Race title Track DateBusch ClashDaytona International Speedway, Daytona BeachFebruary 10Gatorade Twin 125 QualifiersFebruary 141Daytona 500February 172Pontiac Excitement 400Richmond International Raceway, RichmondFebruary 243Goodwrench 500North Carolina Motor Speedway, RockinghamMarch 34Motorcraft 500Atlanta Motor Speedway, HamptonMarch 17–185TranSouth 500Darlington Raceway, DarlingtonApril 76Valleydale Meats 500Bristol International Raceway, BristolApril 147First Union 400North Wilkesboro Speedway, North WilkesboroApril 218Hanes 500Martinsville Speedway, RidgewayApril 289Winston 500Talladega Superspeedway, TalladegaMay 6Winston OpenCharlotte Motor Speedway, ConcordMay 19The Winston10Coca-Cola 600May 2611Budweiser 500Dover Downs International Speedway, DoverJune 312Banquet Frozen Foods 300Sears Point Raceway, SonomaJune 913Champion Spark Plug 500Pocono International Raceway, Long PondJune 1614Miller Genuine Draft 400Michigan International Speedway, BrooklynJune 2315Pepsi 400Daytona International Speedway, Daytona BeachJuly 616Miller Genuine Draft 500Pocono International Raceway, Long PondJuly 2117DieHard 500Talladega Superspeedway, TalladegaJuly 2818Budweiser at The GlenWatkins Glen International, Watkins GlenAugust 1119Champion Spark Plug 400Michigan International Speedway, BrooklynAugust 1820Bud 500Bristol International Raceway, BristolAugust 2421Heinz Southern 500Darlington Raceway, DarlingtonSeptember 122Miller Genuine Draft 400Richmond International Raceway, RichmondSeptember 723Peak Antifreeze 500Dover Downs International Speedway, DoverSeptember 1524Goody's 500Martinsville Speedway, RidgewaySeptember 2225Tyson/Holly Farms 400North Wilkesboro Speedway, North WilkesboroSeptember 2926Mello Yello 500Charlotte Motor Speedway, ConcordOctober 627AC Delco 500North Carolina Motor Speedway, RockinghamOctober 2028Pyroil 500KPhoenix International Raceway, PhoenixNovember 329Hardee's 500Atlanta Motor Speedway, HamptonNovember 17

Races No.RacePole positionMost laps ledWinning driverBusch ClashDerrike CopeDale EarnhardtDale EarnhardtChevroletGatorade Twin 125 #1Davey AllisonDavey AllisonDavey AllisonFordGatorade Twin 125 #2Ernie IrvanDale EarnhardtDale EarnhardtChevrolet1Daytona 500Davey AllisonKyle PettyErnie IrvanChevrolet2Pontiac Excitement 400Davey AllisonRicky RuddDale EarnhardtChevrolet3GM Goodwrench 500Kyle PettyKyle PettyKyle PettyPontiac4Motorcraft 500Alan KulwickiBill ElliottKen SchraderChevrolet5TranSouth 500Geoff BodineMichael WaltripRicky RuddChevrolet6Valleydale Meats 500Rusty WallaceRicky RuddRusty WallacePontiac7First Union 400Brett BodineBrett BodineDarrell WaltripChevrolet8Hanes 500Mark MartinDale EarnhardtDale EarnhardtChevrolet9Winston 500Ernie IrvanDale EarnhardtHarry GantOldsmobileWinston OpenMichael WaltripMichael WaltripMichael WaltripPontiacThe WinstonDavey AllisonDavey AllisonDavey AllisonFord10Coca-Cola 600Mark MartinDavey AllisonDavey AllisonFord11Budweiser 500Michael WaltripDale EarnhardtKen SchraderChevrolet12Banquet Frozen Foods 300Ricky RuddRusty WallaceDavey AllisonFord13Champion Spark Plug 500Mark MartinErnie IrvanDarrell WaltripChevrolet14Miller Genuine Draft 400Michael WaltripDavey AllisonDavey AllisonFord15Pepsi 400Sterling MarlinErnie IrvanBill ElliottFord16Miller Genuine Draft 500Alan KulwickiErnie IrvanRusty WallacePontiac17DieHard 500Sterling MarlinDale EarnhardtDale EarnhardtChevrolet18Budweiser at The GlenTerry LabonteErnie IrvanErnie IrvanChevrolet19Champion Spark Plug 400Alan KulwickiDavey AllisonDale JarrettFord20Bud 500Bill ElliottJimmy SpencerAlan KulwickiFord21Heinz Southern 500Davey AllisonHarry GantHarry GantOldsmobile22Miller Genuine Draft 400Rusty WallaceDavey AllisonHarry GantOldsmobile23Peak AntiFreeze 500Alan KulwickiHarry GantHarry GantOldsmobile24Goody's 500Mark MartinHarry GantHarry GantOldsmobile25Tyson Holly Farms 400Harry GantHarry GantDale EarnhardtChevrolet26Mello Yello 500Mark MartinMark MartinGeoff BodineFord27AC Delco 500Kyle PettyHarry GantDavey AllisonFord28Pyroil 500Geoff BodineDavey AllisonDavey AllisonFord29Hardee's 500Bill ElliottMark MartinMark MartinFord

Busch Clash The Busch Clash, an invitational event for all Busch Pole winners the previous year, was held February 10 at Daytona International Speedway. The starting lineup was decided by random draw. Derrike Cope drew the pole.

Top-ten results: #3 - Dale Earnhardt #6 - Mark Martin #9 - Bill Elliott #4 - Ernie Irvan #2 - Rusty Wallace #25 - Ken Schrader #42 - Kyle Petty #5 - Ricky Rudd #11 - Geoff Bodine #26 - Brett Bodine

After several years of mediocre competition, the race's format was slightly re-tooled. Instead of a single 20-lap sprint, the race was divided into two 10-lap segments. After the first 10-lap half, the caution was displayed (caution laps did not count), freezing the field. The field was inverted for the second 10-lap half. Prize money was awarded for finishing positions in both halves, encouraging drivers to race hard during the first segment, and not hold back or "sandbag" in order to start up front for the second half.

Gatorade 125s The Gatorade 125s, qualifying races for the Daytona 500 were held February 14 at Daytona International Speedway. Davey Allison and Ernie Irvan won the pole for each race, respectively.

Top-ten results (Race One): #28 - Davey Allison #43 - Richard Petty #12 - Hut Stricklin #1 - Rick Mast #5 - Ricky Rudd #33 - Harry Gant #30 - Michael Waltrip #9 - Bill Elliott #21 - Dale Jarrett #11 - Geoff Bodine

Top-ten results (Race Two): #3 - Dale Earnhardt #4 - Ernie Irvan #42 - Kyle Petty #2 - Rusty Wallace #17 - Darrell Waltrip #22 - Sterling Marlin #75 - Joe Ruttman #88 - Buddy Baker #6 - Mark Martin #68 - Bobby Hamilton

Daytona 500 by STP The Daytona 500 by STP was held on February 17 at Daytona International Speedway. Davey Allison won the pole.

Top-ten results: #4 - Ernie Irvan #22 - Sterling Marlin #75 - Joe Ruttman #1 - Rick Mast #3 - Dale Earnhardt #21 - Dale Jarrett −1 lap #27 - Bobby Hillin Jr. −1 lap #7 - Alan Kulwicki −1 lap #5 - Ricky Rudd −1 lap #68 - Bobby Hamilton −1 lap