The 1989 Buffalo Bills season was the franchise's 30th overall season as a football team and the 20th in the National Football League. The Bills finished in first place in the AFC East and finished the National Football League's 1989 season with a record of 9 wins and 7 losses. Although Buffalo won the division and qualified for the postseason, their record was a drop off from their 12–4 mark in 1988.

The team was nicknamed the Bickering Bills because of a rash of internal conflicts within the team. During a Monday Night loss to the Denver Broncos, star quarterback Jim Kelly could be seen arguing with wide receiver Chris Burkett, which led to the latter's last game with the team, as he was released shortly after the game.^[1]

Kelly was injured in a week 5 blowout loss to the Indianapolis Colts and subsequently blamed his offensive line's blocking, notably offensive tackle Howard Ballard, for contributing to his injury.^[2]

In the week leading up to a week-8 matchup with Miami, assistant coaches Tom Bresnahan and Nick Nicolau got into a fistfight while the two were reviewing game film.^[1]

The biggest blowup occurred when starting running back Thurman Thomas, asking to address Jim Kelly's criticism of the offense, and the pass-catching ability of running back Ronnie Harmon in particular, criticized Kelly himself on a Rochester, New York television show. When asked what position the Bills could upgrade at, Thomas replied, "Quarterback." Thomas claimed at first that it was a joke, but later, when appearing on Paul Maguire's Budweiser Sportsline show, he stated that the team didn't appreciate Kelly's public criticism and that Kelly should elevate his level of play.^[3][4]

Before the season, future Hall of Fame defensive end Bruce Smith was offered a large contract by Denver (US$7.5 million over five years), one that the Bills chose to match to retain Smith.^[8] In 1989, Smith became the Bills' all-time sack leader when he reached his 52nd sack; he would end his 19-year career with 200, the most of any NFL player all-time.

Despite the internal strife the Bills experienced, they had some memorable wins. The Bills started the season with a last-second victory at Miami. The Dolphins led 24–13 in the fourth but Buffalo scored on a Flip Johnson touchdown catch, then with two seconds left on the clock, quarterback Jim Kelly dropped back to pass, but ran the ball in to the end zone as time expired, securing a 27–24 win.^[9]

In Week Three, the Bills traveled to the Houston Astrodome and faced the "Run, and Shoot" Oilers. The Bills raced to a 27–10 lead in the third, but the Oilers exploded and the two teams combined for 45 points to force overtime. In overtime, a missed Tony Zendejas kick allowed the Bills to win on Jim Kelly's 28-yard score to Andre Reed. The 47–41 win would become the highest-scoring game between the two franchises. Kelly finished with five touchdown throws.

In Week Six the Bills hosted the undefeated Los Angeles Rams, with backup quarterback Frank Reich subbing for an injured Jim Kelly. The two clubs combined for 26 fourth-quarter points, and with 77 seconds remaining Reich started a drive from the Buffalo 36 yard line and with sixteen seconds left Andre Reed caught the winning eight-yard touchdown.

In Week Thirteen, on Monday Night Football, the Bills lost to the Seattle Seahawks 17–16, which included Seahawk Steve Largent running in a botched extra-point attempt. Dave Krieg's 51-yard touchdown in the fourth was ultimately the 1-point difference.

The Bills then lost their next two games (to the Saints and 49ers) before securing the AFC East title with a shutout road win over the New York Jets.

• Shane Conlan, Pro Bowl Selection
• Kent Hull, Pro Bowl Selection
• Bruce Smith, Pro Bowl Selection
• Thurman Thomas, Pro Bowl Selection
• Thurman Thomas, NFL Combined Yards from Scrimmage Leader

• List of NFL teams affected by internal conflict