Fraser has signed a five-year contract at the St. James’ Park and joins former Bournemouth teammate Callum Wilson in moving to the North East.
Fraser’s contract with Bournemouth ended at the end of June but he refused to sign a short-term extension that would have enabled him complete the coronavirus-hit 2019/2020 season with the Cherries. Bournemouth were eventually relegated.
The 26-year-old Scotland international featured 28 times in the Premier League last season, scoring just once and providing four assists but those figures represented a significant drop compared to seven goals and 14 top flight assists he posted in the 2018/2019 season.
In a statement, Fraser said: "I'm absolutely buzzing for it - I came down to see the place the other day and it was all just good things; the manager, the place, the fans, the messages I've been getting.
"It was just a no-brainer, really, to play in such a big stadium with such passionate fans, and being back up in the north again is big as well.
"So I'm really looking forward to it and I just can’t wait to show everyone what I can do, help the team and help us get back to where we belong."
Magpies' boss Steve Bruce added: "I'm delighted to bring Ryan to Newcastle United. We have held off big competition to get his signature and that says a lot about what this club has to offer.
"His ability and his contributions on the pitch speak for themselves and I'm looking forward to seeing him getting to work in a Newcastle shirt.
"He has wonderful chemistry on the pitch with Callum Wilson, which excites me, and I hope it excites our supporters ahead of the new season."
