The 2005 Colorado Buffaloes football team represented the University of Colorado at Boulder in the 2005 NCAA Division I-A football season. The previous year's team won the Big 12 North Conference. That marked the third Big 12 North championship for the Buffaloes in four years. The team had expectations to improve on their winning and appeared to be on the right track with a 7–2 record to begin the season. But in the end, head coach Gary Barnett had his contract bought out and Colorado suffered four straight losses including an embarrassing 70–3 loss to Texas in the Big 12 Championship Game. They finished the season 7–6. In the 2005 Champs Sports Bowl against Clemson, Mike Hankwitz acted as interim head coach, even though Dan Hawkins had been hired as the new head coach. Hawkins coached his final game with Boise State in the MPC Computers Bowl game the day after Colorado played.

Colorado had plenty of returning players (they graduated only 11 seniors, returned 50 letterman and 17 starters) and were ranked in the Top 25 in 4 pre-season polls. They were also picked to win the Big 12 North in 9 rankings.

QB Joel Klatt had a solid lock on his starting position. But there was uncertainty of who would be the starting RB, through TB Lawrence Vickers had the inside chance and main competition from Hugh Charles. The shining part of the team was Special Teams, with kicker Mason Crosby and punter John Torp. Other notable returners on offense were tight ends Joe Klopfenstein and Quinn Sypniewski, wide receiver Evan Judge, and most of the offensive line: Brian Daniels, Jr.; Mark Fenton, Clint O'Neal and Gary Moore.

Defense was also solid with few key losses and most returning: (line) James Garee, Alex Ligon, Vaka Manupuna; (linebackers) Thaddaeus Washington, Jordon Dizon, Akarika Dawn, Brian Iwuh; (backs) Terrence Wheatley, Lorenzo Sims, Tyrone Henderson, Dominique Brooks.

Although Colorado won the Big 12 North, they back-doored their way in because they lost their two final conference games and needed Iowa State to lose their final game in order to win. Iowa State missed a field goal in OT and thus, Colorado won the Big 12 Conference North Division Title. In the Big 12 Conference Title game, Joel Klatt suffered a concussion and was taken to a hospital. His career at Colorado was then over, as he sat out the bowl game. The key game of the season was Colorado's game against Iowa State. Colorado was leading the game into the fourth quarter, but gave up two touchdowns late in the game to go on and lose. It seemed their spirit was broken as they never pulled it together after that and were never really in any game they played afterwards.^{[citation needed]}

They also ended up setting the school records for most penalties in a season with 123 (since 1996) and most penalty yards in a season with 1084 yards. They were the most penalized team in NCAA Division I-A and 116th (of 117 teams) in penalty yards per game with 83.38 (Texas Tech was 117th with 83.42).^[1] They had 35 flags thrown in the last four games of the season which helped with their downfall. Penalties often came at bad times to stop a drive or assist an opponent's drive just when they needed it.

S=Scholarship; WO=Walk-On; #/#—clock as of 2005 season, i.e., 3/2: three years available to play two in eligibility. #L=indicates number of letters earned through 2004; HS=high school; JC=junior college transfer; RS=freshman redshirt in 2004; TR=transfer; VR=varsity reserve performer.