The Serie A outfit strengthen their midfield with the Brazil Under-20s international ahead of the 2013-14 campaign, the departing Santos man signing a five-year contract
The 20-year-old had long been linked with a move to the Serie A side and has now signed a five-year deal with the Biancocelesti to complete his transfer, the Italian outfit have confirmed on their official website.
Anderson is a product of the Santos youth academy and made his official first-team debut for the Brazilian giants in October 2010.
The midfielder had since developed into a key player, attracting the interest of a number of European sides in the process.
Lazio initially struck a deal with Santos to sign Anderson in January but the move then fell through following complications over the necessary paperwork.
Anderson will now continue his career in the Italian capital after all, though, as he joins compatriots Hernanes, Ederson and Andre Dias.