The 2005 NFL season was the 86th regular season of the National Football League (NFL).

Patriots

Bills

Dolphins

Jets

Bengals

Ravens

Steelers

Browns

Colts

Titans

Jaguars

Texans

Broncos

Chiefs

Raiders

Chargers

AFC teams: West, North, South, East

Cowboys

Giants

Eagles

Redskins

Bears

Lions

Packers

Vikings

Falcons

Panthers

Buccaneers

Cardinals

Rams

Seahawks

49ers

Various Locations
Saints

NFC teams: West, North, South, East

Regular season play was held from September 8, 2005 to January 1, 2006. The regular season also saw the first ever regular season game played outside the United States, as well as the New Orleans Saints being forced to play elsewhere due to damage to the Superdome and the entire New Orleans area by Hurricane Katrina.

The playoffs began on January 7. The New England Patriots' streak of 10 consecutive playoff wins and chance at a third straight Super Bowl title was ended in the Divisional Playoff Round by the Denver Broncos, and eventually the NFL title was won by the Pittsburgh Steelers, who defeated the Seattle Seahawks in Super Bowl XL at Ford Field in Detroit, Michigan on February 5 for their fifth Super Bowl win. This also marked the first time that a sixth-seeded team, who by the nature of their seeding would play every game on the road, would advance to and win the Super Bowl.

The season formally concluded with the Pro Bowl, the league's all-star game, at Aloha Stadium in Honolulu, Hawaii on February 12.

This was also the final full season for Paul Tagliabue as commissioner.

The 2005 NFL Draft was held from April 23 to 24, 2005 at New York City's Jacob K. Javits Convention Center. With the first pick, the San Francisco 49ers selected quarterback Alex Smith from the University of Utah.

• The "horse-collar tackle", in which a defender grabs inside the back or side of an opponent's shoulder pads and pulls that player down, is prohibited.^[1] Named the "Roy Williams Rule" after the Dallas Cowboys safety whose horse collar tackles during the 2004 season caused serious injuries to several players.
• Peel-back blocks (in which an offensive player blocks a defender who is moving back toward the direction of his own end zone) below the waist and from the back are now illegal.
• Unnecessary roughness would be called for blocks away from the play on punters or kickers, similar to the same protection quarterbacks have after interceptions.
• When time is stopped by officials prior to the snap for any reason while time is in, the play clock resumes with the same amount of time that remained on it – with a minimum of 10 seconds. Previously, the play-clock would be reset to 25 seconds.
• During field goal and extra point attempts, the defensive team will be penalized for unsportsmanlike conduct if it calls consecutive timeouts in an attempt to "ice" the kicker. Previously, the second timeout request was only denied by officials, and thus could be used to distract the kickers.
• Players cannot run, dive into, cut, or throw their bodies against or on an opponent who is out of the play or should not have reasonably anticipated such contact.
• If the defensive team commits a dead ball foul following the end of the half, the offensive team may choose to extend the period for one more play. Previously, the half automatically ended without the defensive team being penalized.
• The prohibition on offensive players pushing other offensive players was removed, allowing plays such as the "Bush Push" (later renamed the "Tush Push" popularized by the Philadelphia Eagles years later).
• During a punt, if the kicking team illegally touches the ball inside the 5-yard line, the receiving team has the option of either treating the result as a touchback or replaying the down with a 5-yard penalty against the kicking team. Previously, the receiving team's only options were either the latter or taking over possession at the spot of the foul. This change prevents an ineligible player from keeping a kick from entering the end zone and becoming a touchback.
• If the kicking team commits a penalty, the receiving team can have the option of adding the penalty yardage to the return or taking a penalty and forcing the kicking team to rekick the ball. Previously they could take the latter or decline the penalty.
• If a team calls for an instant replay challenge after it has used all its challenges or is out of timeouts, it will be assessed an unsportsmanlike conduct penalty. The penalty will also be assessed if a team calls for a challenge inside of two minutes of either half or overtime, when only the replay assistant can initiate reviews. Previously, the request was only denied by the Referee. This change was made to prevent head coaches from constantly stopping the game for any reason, including to just argue with the Referee.
• Teams are only able to request an instant replay challenge by tossing their red flag to get the attention of officials. The league decided to do away with the electronic pager/vibrating alert system used by head coaches because practically all of them always used their red flags instead of their pagers anyway. (However, the replay assistant will still use the pagers to notify the officials of a replay request.)

• Steve Belichick former fullback and father of Patriots and Browns head coach Bill Belichick
• Wellington Mara Owner of the New York Giants
• Bob Tisch Owner of the New York Giants
• Hank Stram former head coach of the Kansas City Chiefs

Within each conference, the four division winners and the top two non-division winners with the best overall regular season records) qualified for the playoffs. The four division winners are seeded 1–4 based on their overall won-lost-tied record, and the wild card teams are seeded 5–6. The NFL does not use a fixed bracket playoff system, and there are no restrictions regarding teams from the same division matching up in any round. In the first round, dubbed the wild-card playoffs or wild-card weekend, the third-seeded division winner hosts the sixth-seed wild card, and the fourth seed hosts the fifth. The 1 and 2 seeds from each conference received a first-round bye. In the second round, the divisional playoffs, the number 1 seed hosts the worst-surviving seed from the first round (seed 4, 5, or 6), while the number 2 seed will play the other team (seed 3, 4, or 5). The two surviving teams from each conference's divisional playoff games met in the respective AFC and NFC Conference Championship games, hosted by the higher seed. Although the Super Bowl, the championship round of the playoffs, is played at a neutral site, the designated home team is based on an annual rotation by conference.^[6]

The following teams and players set all-time NFL records during the season:

The New Orleans Saints played in Baton Rouge's Tiger Stadium for four games and in San Antonio's Alamodome for three games due to Louisiana Superdome damaged by Hurricane Katrina. Tiger Stadium's goalposts did not conform to NFL standards due to (a) two supports instead of one and (b) white paint instead of gold. The NFL granted the Saints dispensation to keep LSU's goalposts in place for their games.

In addition, with the RCA and Edward Jones domes both removing their AstroTurf surfaces in favor of the newer next-generation FieldTurf surface, the old first-generation AstroTurf surface ceased to be used in the NFL.

Pro Player Stadium was renamed Dolphins Stadium. Pro Player's parent Fruit of the Loom had filed for Chapter 11 bankruptcy protection back in 1999, and the Pro Player label was discontinued, but that stadium name was kept for several more years.

• The Arizona Cardinals unveiled a new uniform design featuring trim lines to the outside shoulders, sleeves, and sides of the jerseys and pants. The cardinal helmet logo was also redesigned to be more aggressive.
• The Buffalo Bills added a third alternative uniform: their 1960s throwbacks with the white helmets and red standing bison logo.
• The Detroit Lions added black third alternate uniforms at the urging of president Matt Millen, a former Raider.
• The New York Giants changed their white jerseys to mimic the team's design used in the 1950s. When they last made major changes in 2000, the Giants only modified their blue jerseys to the 1950s look while keeping many of the 1980s elements on their white jerseys, such as the 1980s blue collars instead of the 1950s white collars and red shoulder stripe design.
• The St. Louis Rams began wearing navy pants with their white jerseys for selected games.

This was the eighth and final year under the league's broadcast contracts with ABC, CBS, Fox, and ESPN to televise Monday Night Football, the AFC package, the NFC package, and Sunday Night Football, respectively.

While CBS and Fox renewed their television contracts to the AFC and the NFC packages, respectively,^[10] 2005 marked the final season that ABC held the exclusive rights to televise Monday Night Football. When the TV contracts were renewed, the rights to broadcast MNF were awarded to Disney-owned corporate sibling ESPN. NBC then won the rights to televise Sunday Night Football, marking the first time that the network broadcast NFL games since Super Bowl XXXII in 1998.^[11] While the NFL had indicated that it wanted SNF to become the new night for its marquee game, ABC declined to renew, citing that it had lost millions of dollars on the MNF despite generating high ratings, and the network wanted to continue airing the TV series Desperate Housewives on Sunday nights.^[12][13] ABC would not air NFL games again until they began simulcasting ESPN's Wild Card playoff game in January 2016, and began simulcasting select MNF games in 2020.

Cris Collinsworth left Fox to sit out the 2005 season before joining NBC as a studio analyst the following year, leaving Fox's lead broadcasting team of Joe Buck and Troy Aikman in a two-man booth.^[14]