The 20-year-old signed for the club in a £2million deal last summer after impressing during a loan spell from Monaco in Wolves' Championship title-winning campaign.
He played 17 times in the Premier League in 2018/18, starting seven games, and club bosses believe he has the potential to be part of the first-team squad for many years to come.
Sporting director Kevin Thelwell said of the youngster: "Ruben has developed impressively since joining the club two seasons ago and is an important part of Nuno’s squad.
"As the club has grown in recent times, Ruben has done the same, and performed commendably when called upon in the Premier League last season.
"Off the pitch, he provides a mature head for someone so young and is a popular personality inside the dressing room.
"We’re excited to watch and help Ruben develop further this coming season and, after his impact in the two Asia Trophy games, we hope he’ll kick on once again."