2005 Detroit Lions season

The 2005 season was the Detroit Lions' 76th in the National Football League (NFL) and the third and final under head coach Steve Mariucci. The Lions failed to improve on their 6–10 record from 2004.

The Lions began their 2005 season with a 17–3 win over the rival Green Bay Packers. However, the next week, the Lions were throttled, 38–6, by the Chicago Bears in Chicago. By week 10, the Lions had a 4–5 record after they had defeated the Arizona Cardinals 29–21 at home. However, the Lions lost five consecutive games following that win, and were eliminated from the playoffs with a 16–13 overtime loss to the Packers. The Lions would win one more game for the rest of the season, which was a 13–12 win over the New Orleans Saints. The season concluded with a 35–21 loss to the eventual Super Bowl XL champion Pittsburgh Steelers.

During the season, after the Lions lost 27–7 on Thanksgiving Day to the Atlanta Falcons, the Lions fired Steve Mariucci, and hired Dick Jauron to be the interim head coach for the remainder of the season.