The 25-year-old arrives at Turf Moor on a four-year deal that reportedly matches the sum paid last year by Sean Dyche’s side to coax striker Chris Wood from Championship outfit Leeds United.
Gibson appeared in all of Boro’s Premier League fixtures during the 2016-17 campaign and remained with them following their relegation to the second tier, featuring prominently as they reached the play-off semi-finals in an unsuccessful attempt to return to the top flight.
“I’m absolutely delighted. It’s a big step for me and one I’m really, really excited about,” Gibson said.
“There’s a good feel about the place. Burnley is a club that recently has had some fantastic success and I’ve had some great battles against them myself.
“I’m looking forward to wearing their colours.”
Burnley unexpectedly secured their best-ever finish in the Premier League era last season, reaching seventh, and secured European football for the first time in half-a-century, both of which factored into Gibson’s decision to depart his boyhood club.
“I’ve played for Middlesbrough for 15 years since I was a boy so it’s a huge step” he added.
“Now it’s done and dusted I just want to get cracked on and fight to win my place in the team and get to know the boys and be very much part of what’s happening.
Quoting Sir Alex Ferguson, Gibson further added: ““The measure of a fantastic team is not to do something once, but to repeat that time and time again.
“Sean Dyche and the team and everyone here did such a fantastic job last year in finishing seventh and qualifying for the Europa League. This is just the start of things to come.”