The 30-year-old's current deal was set to expire in the 2014-15 season, so the Toffees moved quickly to retain his services for another four years due to his outstanding form this season.
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.
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"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 joined the club in 2007 from Sheffield United in a £4 million deal and has established himself as a key player in David Moyes' side.
In his five years at the club he's made 195 appearances and was named as Everton’s player and players’ player of the year in 2009 where he fired the Toffees into the FA Cup final scoring the winning penalty in the semi-final victory over Manchester United.
However, the centre-back was to cruelly miss the final as ruptured his cruciate ligament a week before the game. His excellent form for Everton has seen earn 16 England caps so far scoring one goal against Italy in August 2012.