The 28-year-old winger has joined from Tottenham on a three-year deal for an undisclosed fee having spent time on loan at Goodison Park last season.
Everton officials lodged the paperwork before the 6pm deadline and the transfer was rubber-stamped earlier in the evening on Tuesday.
CONFIRMED: We have completed the signing of @aaron7lennon from Tottenham on a three-year deal. #WelcomeBackAaronpic.twitter.com/uAGH7QCxTu
— Everton (@Everton) September 1, 2015