(Adds Barkley, Martinez quotes)
Barkley, 20, enjoyed a breakthrough season under manager Roberto Martinez last term, earning widespread praise for some dynamic performances and a place in England's World Cup squad.
"As soon as I got told about it, I knew I was going to sign," Barkley told the club's website (www.evertonfc.com).
"It means everything, signing the new contract. It is a dream to have been playing for Everton all my life and today is a great thing for me.
"I am settled in at Everton, this is the club I love. I see it as my home, I never think of anything away from Goodison."
Martinez added: "It is a four-year deal, which reflects his new role and his development. This is as big news as we could get."
Barkley's development into one of English soccer's leading talents had led to media speculation that rival clubs, including Manchester United and Manchester City, would bid for him in the close season.
He appeared in each of England's three group games at the World Cup after helping Everton finish fifth in the Premier League last season.
The club's chairman, Bill Kenwright, said: "Everton and Ross have always been the perfect fit - Roberto has made it even more special.
"This was an important agreement and, I have to say, was conducted in a way that showed clearly the devotion to Everton Football Club of everyone involved." (Writing by Stephen Wood, editing by Justin Palmer and Ken Ferris)
- Sports & Recreation
- Ross Barkley
- Roberto Martinez