The 33-year-old, crowned African Player of the Year a record four times, scored nine league goals in 21 games at Stamford Bridge after joining from Russia's Anzhi Makhachkala.
Eto'o, who has won 118 caps and scored a record 56 goals for Cameroon, signed a two-year deal at Goodison Park.
"I have been very impressed by the style of play Everton adopt," Eto'o told the club's website, having been lured by manager Roberto Martinez's footballing philosophy.
"I was impressed with his enthusiasm but also by the knowledge of football that Roberto Martinez carries, his vision of football ..."
l Manchester United have signed Argentina midfielder Angel di Maria from Real Madrid for a British record transfer fee of £59.7 million, the English Premier League club announced yesterday.
The 26-year-old's move, on a five-year contract, shatters the previous British record fee of £50m paid by Chelsea to sign Spain striker Fernando Torres from Liverpool in 2011.