The England international, 30, joined the Toffees from Sheffield United in 2007 for a fee of £4million and has been a mainstay of David Moyes' rearguard ever since.
Everton chief executive Robert Elstone told the club's official website: "We are delighted Phil has agreed to commit his long-term future here at Goodison Park.
"Phil is a hugely important and influential player and I, like many Evertonians, look forward to seeing him play in a blue shirt for many years to come.
"Discussions have been taking place for a short while and, now they are completed, I would like to thank Phil and his representatives for the professionalism and courtesy shown throughout those negotiations."
Jagielka, who was Everton's player and players' player of the year in 2009, made his England debut against Trinidad and Tobago in 2008 and was a member of Roy Hodgson's Euro 2012 squad over the summer.