MacIntyre was fired after losing six straight games following a 5-0 start.
Colorado has fired head coach Mike MacIntyre, athletic director Rick George announced Sunday.
Quarterbacks coach Kurt Roper was named the interim coach and will lead the Buffaloes in their regular-season finale against California next week.
The news was first reported by ESPN's Chris Low.
Colorado has lost each of its last six games after opening the season 5-0. The team is currently in last place in the Pac-12 South division, with a 2-6 record in conference play.
In 2016, MacIntyre led the Buffaloes to a 10-4 record and a Pac-12 South title, the first in program history. He was also honored as 2016 Pac-12 Coach of the Year.
Colorado hired MacIntyre in December 2012. He coached the Buffaloes for six seasons, compiling a 30-44 record.