The 33-year-old’s current deal with Boro was due to expire and the Scotland international has now signed a pre-contract with the MLS side.
“I’ve enjoyed my time with Middlesbrough enormously and the move to England has been good for me and for my career,” said Robson.
“My immediate priority is to help Boro win promotion to the Premier League, where the club and their supporters deserve to be.
“With the squad we have, there’s every chance we can do that, although we all know it’s going to be hard with the league being so tight.
“I’d like to wish Tony Mowbray, the club and the fans, who have welcomed me so warmly since I came here, the very best for the future.
“I’m very excited to be joining Whitecaps and to continue my career in Major League Soccer. My family and I are also looking forward to our move to the beautiful city of Vancouver.
“But I’ll be keeping a very close eye on Boro’s fortunes from Canada and they will always have a special place in my heart.”
