The forward signed on a season-long loan deal.
The 19-year-old attacker, who was part of Spain’s squad at the Under-20 World Cup in Turkey, scored 18 times in 33 matches for Barcelona’s Team B last season.
“Gerard Deulofeu is a real diamond of Spanish football and with incredible footballing talent and I am delighted that he has chosen to take the next step of his career with Everton,” Everton boss Roberto Martinez told the club’s official website.
Deulofeu made one appearance in La Liga last season, coming off the bench against Mallorca, and also featured in the Champions League group stage ties against Spartak Moscow and Benfica.
The signing of Neymar is expected to limit the forward’s appearance for Barcelona in the coming season, thus his being loaned to get more playing time.
Gerard Deulofeu is Everton’s fourth signing of the summer transfer window, with the Toffees having already secured permanent deals for ex-Wigan trio: Arouna Kone, Joel Robles and Antolin Alcaraz.