Everton said on their website (www.evertonfc.com) on Thursday that the 30-year-old centre-back had added two years to an existing deal that runs out at the end of the 2014-15 season.
"We are delighted Phil has agreed to commit his long term future here at Goodison Park," said chief executive Robert Elstone.
"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."
Jagielka joined Everton from Sheffield United in 2007. (Reporting by Alan Baldwin, editing by Ed Osmond)