The 28-year-old, who played a key role in the club's promotion, becomes manager Sean Dyche's first recruit of the close season after joining for an undisclosed fee and signing a three-year deal.
The former England Under-21 international, who scored five goals in 38 games last season, said: "As soon as we secured promotion to the Premier League last season, I wanted to make sure that I signed.
"Coming in on loan is usually difficult but it only took a few weeks here to get settled and it is great to be a permanent Burnley player now, as opposed to a loanee.
"It took a while to get it over the line but now it is all secured I'm really pleased."
The Basildon-born player began his career in non-League football before joining Wolves and later having a loan spell at Watford.
He joined Stoke in the summer of 2012 but was allowed to move to Burnley a year later.
Kightly said: "At the tail end of last season I felt like I was getting back to my best and if I can carry that into next season then I will have a good campaign.
"It'll be a tough start to the campaign with Chelsea at home but you can look at that in two ways and we'll certainly start with a positive mindset.
"People might write us off, but we're certainly not here to make up the numbers and hopefully we can surprise a few people again."