Ganso has signed a five-year contract at the Ramon Sanchez Pizjuan and becomes Sevilla's sixth signing of the summer.
The 26-year-old has made 275 appearances in Brazilian football, scoring 24 goals and making 47 assists.
The attacking midfielder also has eight Brazil caps to his name, but is yet to score for his country.
"I would like to thank Sao Paulo for everything the club has done for me," the midfielder told Sao Paulo's official website.
"Sao Paulo will forever have a place in my heart. But I think the time was right to make the move to Europe".