The 2011 NASCAR Sprint Cup Series was the 63rd season of professional stock car racing in the United States and the 40th modern-era Cup series season. The season included 36 races and two exhibition races, beginning with the Daytona 500 at Daytona International Speedway and ending with the Ford 400 at Homestead-Miami Speedway. The final ten races were known as 2011 Chase for the Sprint Cup.

The 2011 season is considered by many to be one of the greatest and most exciting seasons in Cup Series history. It had the closest points battle in history, with Tony Stewart winning the Drivers' Championship with a victory at the final race of the season in a tiebreaker over Carl Edwards due to having five wins on the season vs. Edwards' one win. To much surprise, Stewart, after barely making the Chase that year and having zero wins when the postseason began, went on to win five of the final ten races and then the title over Edwards, who led the points for most of the year despite only scoring one win early in the season at the Las Vegas. There were eighteen different race winners, the most since 2002. There were also five first-time Cup Series winners, most notably Trevor Bayne, the first of those, with his upset win in the Daytona 500 in just his second career Cup race. The other first-time winners were Regan Smith at Darlington, David Ragan at Daytona in July, Paul Menard at Indianapolis, and Marcos Ambrose at Watkins Glen. Some of those races the first-time winners won are also the biggest and most prestigious on the schedule.

During the 2010 season, NASCAR announced several calendar changes for 2011, including race additions at Kansas Speedway and Kentucky Speedway, and the removal of one race each from Atlanta Motor Speedway and Auto Club Speedway. Once the 2010 season had concluded, NASCAR also announced changes to the point system, and that the fuel changed from Sunoco unleaded to an ethanol blend called 'Sunoco Green E15'.

In addition, Stewart–Haas Racing, owned by Stewart and Gene Haas, won the Owners' Championship, while Chevrolet won their ninth-consecutive Manufacturers' Championship with 248 points. Stewart became the first owner-driver to win a Cup title since Alan Kulwicki in 1992.

This was the final season Cup cars would use carburetors in the engines which goes back to the NASCAR Cups first season in 1949. In 2012 the series would shift to fuel injection.

There were 41 full-time teams in 2011.

In preparation for 2011, Penske Racing made team changes by moving Brad Keselowski, along with his No. 12 team, into the No. 2 Miller Lite car, replacing Kurt Busch and his 2010 team, who moved to the newly formed No. 22 Shell/Pennzoil car. Another change was made by Hendrick Motorsports, who rearranged three of the four-car team. The team moved Steve Letarte with Dale Earnhardt Jr., Alan Gustafson with Jeff Gordon, and Lance McGrew with Mark Martin. On January 7, 2011, Bob Leavine and Lance Fenton announced the formation of Leavine Fenton Racing, and that David Starr drove for the team. In February, another team was formed, FAS Lane Racing, by Frank Stoddard. In March, David Stremme announced his return to the Cup Series with a new team, Inception Motorsports. They ran the No. 30 Chevrolet and attempted to make the spring race at Richmond. In October before the Bank of America 500, it was announced that Sinica Motorsports would join the Cup Series for 3 races in 2011, running the No. 93 Chevrolet with either Bill Elliott or Terry Labonte and that ARCA driver Grant Enfinger would drive for the team for 10–15 races in 2012. (The team ended up only attempting the season-finale at Homestead with Enfinger in 2011, which they failed to qualify for, and no races in 2012.)

Another new team for 2011, America's Racing Team, was scheduled to debut in the Daytona 500 with their No. 76 Chevrolet. The team was formed in 2010 before the July race at Daytona. The team was unique because fans could pay between $44.95 to $1,999.95 to own a portion of it. However, AMR was unable to get off the ground and they did not attempt any races.