Fresh start:Morgan Schneiderlin.Credit:AP
He said in a club statement that he was relishing the prospect of being reunited with Everton manager Ronald Koeman,with whom he worked for one season at Southampton.
"There is a manager in place here that I know,I know he can get the best out of me,I know his style and how he likes to play football. He was very good with me from the start and I enjoyed playing football under him,"Schneiderlin said.
"He was very good for me and,obviously,he was a massive player in his playing days and you can only learn from the best. At Southampton he gave me some great advice to keep improving every day and it was a pleasure to work with him."
Everton said the midfielder had signed a four-and-a-half-year deal for an initial £20 million fee,which could rise to £24 million.
The move comes days after Koeman urged the Everton board to back him in the transfer market after last weekend's FA Cup exit at home to Leicester City.
Everton let slip a one-goal lead at Goodison Park with Nigerian striker Ahmed Musa's second-half double enough to condemn the Merseyside club to a 2-1 third round defeat and the likelihood of another season without silverware.