Dawson, 30, has signed a three-year contract at the KC Stadium, having decided to end a nine-year association with Tottenham that saw him appointed club captain in 2012.
"I have been here for almost a decade and have loved every minute of it," Dawson said on Tottenham's official Twitter feed.
"I would like to say thank you to everyone at the club, including the supporters. We have enjoyed some incredible moments together and I hope the club continues to move forward in the future."
Dawson, who has won four England caps, is the sixth new player to join Hull during the close season after Tom Ince, Jake Livermore, Robert Snodgrass, Andrew Robertson and Harry Maguire.
The centre-back follows in the footsteps of older brother Andy, who used to play for Hull, and will compete with Curtis Davies, James Chester, Paul McShane and Maguire for a role in central defence.
"I know the club well with my family history, with Andy being here," Dawson added. "I'm just ready and raring to go."