The 29-year-old becomes the second new recruit at the Stadium of Light in two days after full-back Billy Jones agreed to join Black Cats boss Gus Poyet on Wearside.
A statement published on Sunderland's official website read: " Sunderland AFC has confirmed that Spanish midfielder Jordi Gomez has agreed a three-year deal at the Stadium of Light and will become a Sunderland player from July 1."
After graduating from the Barcelona academy, Gomez spent two years with Espanyol before joining Roberto Martinez's Swansea on loan in 2008.
He followed his countryman to Wigan in June 2009 and helped the Latics win the FA Cup four years later.
Gomez's last season with Wigan was spent in the Sky Bet Championship and his 11-goal contribution from midfield culminated in him winning the club's player of the year award for the 2013-14 season.
Sunderland, who dramatically escaped the relegation zone to finish 14th in the Premier League last month, are making moves to ensure a more prosperous campaign.
The signings of Jones - also on a three-year deal - and Gomez arrived either side of the news that Uruguayan manager Poyet had committed his future to the Black Cats until 2016 by penning a new contract.
Source : PA
Source: PA