Williams had 18 months left on his previous deal but with Premier League clubs circling, Boro boss Tony Mowbray was keen to tie him down with a new contract.
 
“I’ve always said I wanted to stay,” he said. “I’m happy here and that’s the main thing. I’m settle and get on well with the manager and the lads.
 
“I’ve no reason to leave except for my dream of playing in the Premier League – and I want to get there with this club.
 
“My fiancée has settled here, I know the town and have a lot of friends here. I couldn’t be happier, to be honest.”
 
Middlesbrough manager Tony Mowbray trilled with Williams’ decision to extend his stay at the club.
 
“Rhys is an important cog as we move forward trying to build a team to get us into the Premier League,” he said.
 
“This is an important statement from the club to try to tie down one of the players we feel we can move forward with.”