The 22-year-old attacking midfielder had been linked with Real Madrid and Manchester United after impressing in his two seasons at Valencia having joined them from Benfica.
"Agreement with Valencia for Andre Gomes. The player will both sign and be presented as a new Barcelona player next week," Barca tweeted.
Barcelona have not revealed any more details about the transfer but Marca reported that Gomes will sign a five-year deal and join the Spanish champions for 50 million euros ($55.12 million).
Gomes, under contract with Valencia until June 2020, started 27 league games for the club in the 2015-16 campaign.
A Euro 2016 champion with Portugal, Gomes will become Barca's fourth signing this summer following the arrivals of Samuel Umtiti, Denis Suarez and Lucas Digne.
($1 = 0.9071 euros)
(Reporting by Adriana Garcia)
