The 50-year-old was the longest serving manager in charge of a Premier League club, having been appointed in October 2012.
He led Burnley to two promotions to the Premier League and only signed a new contract until the summer of 2025 last September.
Burnley find themselves in 18th position on the league table, having recorded just four wins all season and have only eight games to salvage their campaign.
Dyche is the tenth Premier League manager to be sacked this season after Xisco Munoz, Nuno Esperito Santo, Dean Smith, Daniel Farke, Rafael Benitez, Claudio Ranieri, Steve Bruce, Ole Gunnar Solskjaer and Marcelo Bielsa.
A club statement confirming his departure said: “Burnley Football Club can confirm the club has parted company with manager Sean Dyche, assistant manager Ian Woan, first-team coach Steve Stone and goalkeeping coach Billy Mercer.”
Confirming Dyche’s departure, chairman Alan Pace said: “Firstly, we would like to place on record our sincere thanks to Sean and his staff for their achievements at the club over the last decade.
“During his time at Turf Moor, Sean has been a credit both on and off the pitch, respected by players, staff, supporters, and the wider football community.
“However, results this season have been disappointing and, while this was an incredibly difficult decision, with eight crucial games of the campaign remaining, we feel a change is needed to give the squad the best possible chance of retaining its Premier League status.
“The process of replacing Sean has begun and further announcements will be made to supporters in due course.”