The defender's form for the Toffees, since his 2007 move from Sheffield United, has earned him a regular place in the England squad.
His existing deal wasn't due to expire until 2014 but the club were keen to reward the 28-year-old with an improved agreement to ward off interest from potential suitors including Arsenal.
"I'm really pleased," Jagielka said. "We had talks a while ago and I knew it would only be a case of getting it signed and sealed and you can tell by the smile on my face that I am absolutely delighted to commit my future to Everton.
"I had a little while left on my last one but it is obviously nice to get a new one.
"I can concentrate on the football and hopefully there are exciting times ahead for me and the club."