2008 Detroit Lions season

The 2008 season was the Detroit Lions' 79th in the National Football League (NFL), and their 75th since moving to Detroit from Portsmouth, Ohio. The Lions made history by becoming the first team since the schedule was expanded to 16 games to finish winless. It is one of only four winless seasons since the merger.

2008 was the third season under head coach Rod Marinelli, and the Lions entered the season looking to improve upon their 7–9 record the year before, their best since the 2000 season. However, the Lions instead suffered one of the worst seasons in NFL history, finishing 0–16 and joining the expansion1976 Tampa Bay Buccaneers as only the second team since the AFL–NFL merger to finish a full-length season winless, and the first under the 16-game schedule in place from 1978 to 2020. The Lions gave up a franchise-record 517 points during the season, coming within 16 of matching the 1981 Colts' record of 533 points allowed. The Lions' 32.31 points per game allowed on defense is the third worst of any NFL team since the 1960s, bettering only the 1966 Giants (35.79 PPG) and the aforementioned 1981 Colts (33.31 PPG). The 517 points-allowed mark has since been eclipsed by the 2020 team, who allowed 519 points.

The Lions were mathematically eliminated from playoff contention with a Week 11 loss to the Carolina Panthers. Embattled team president, general manager, and CEO Matt Millen, who had served in those roles since 2001, was fired on September 24, 2008. Marinelli was fired after the season ended along with most of his staff.

To celebrate their 75th season playing as the Lions, the team wore a special throwback replica of the uniforms used in 1934, their first season as the Lions, for two home games. The uniforms had blue jerseys with silver lettering, solid silver pants, blue socks, and solid silver helmets (as helmets were leather back then). This replaced their black alternate jersey used in the 2005 to 2007 seasons.

While unique when it happened, the 2008 Lions' 0–16 record was later matched by the 2017 Cleveland Browns. Combined with the Lions' 2–14 record the next year, this was the worst two season record since the merger until it was surpassed by the Browns, who had a 1–15 record in 2016 followed by an 0–16 record in 2017. With the NFL later extending the season to 17 games beginning in 2021, an 0–16 record is now no longer a possibility, although such a start can be achieved, regardless of how the 17th game goes. As a result, the 2008 Lions and 2017 Browns are the only two teams to go winless in a 16-game season.