The 20-year-old, who was a previous Liverpool and a Chelsea target, has put pen to paper on a five-year deal with the Molineux club.
Neves is set to link up once more with his former boss Nuno Espirito Santo, who was key to getting the sensational transfer over the line.
Neves will join a growing Portuguese contingent at Molineux, which includes £13m winger Helder Costa, centre-back Roderick Miranda and midfielder Ivan Cavaleiro – all of them clients of super agent Jorge Mendes.
Speaking on the club’s official website, Neves said: “I’m very excited to play at this club. It is a very big club and I hope to help the team to win their goals.
“I have always wanted to play in England and we have a good team. I think we can do good things this season.
“It is also a good opportunity for me to work again with a trainer [Nuno Espirito Santo] I worked with last year.
“I am very excited to start and to play in front of the fans – I love that.”
Wolves boss Nuno added: “Ruben is a very good player who can bring new things to our squad. I know him well, I worked with him last year – he’s a good player.
“When a player is captain of a big team like Porto in a Champions League game at such a young age, it means a lot.
“He was very pleased to come here, it’s a good challenge for him.”