The Bears finished in the cellar of the NFC North for the third consecutive season under Fox, who was hired by the team in January 2015 after a four-year stint as the Denver Broncos' coach.
Fox coached the Broncos to a 46-18 record, four consecutive division titles and a Super Bowl appearance, but that level of success did not travel with him to the Windy City.
"Thank you to all the players, coaches, the city of Chicago and Bears fans everywhere, your passion for the game and this team is unmatched in the NFL," Fox said in a statement released by the team. "Today is the tough part of our results-oriented business but I wish the Bears organization the best for years to come."
General manager Ryan Pace is expected to hold a press conference at approximately 4 p.m. CT on Monday at the PNC Center at Halas Hall.
It simply hasn't worked in Chicago, where the Bears have gone 6-10, 3-13 and 5-11 in Fox's three seasons. In 2017, they were 0-6 vs. the NFC North, marking the franchise's first winless season in their division in nearly 50 years.
The 62-year-old Fox owns a 133-123 record with Chicago, Denver and the Carolina Panthers.