Middlesbrough have handed four of their youngsters pro contracts.
Defender Seb Hines, 19, who scored on his debut in the 4-3 FA Cup third-round replay victory over Hull last season, has signed a two-year deal.
Nineteen-year-old winger Owens and Australia-born defender Williams, 18, have penned two-year deals, while full-back Grounds, also 19, has signed a 12-month contract.
Academy director Dave Parnaby said: "All three of our new professionals have been given contracts because of their gradual improvement.
"It is the view of the coaching staff and management that they still have potential to fulfil and hopefully they will do that with Middlesbrough.
"All three have played significant roles for Steve Agnew's reserve side, but they each now need to push further and challenge any player in their position who is ahead of them in the pecking order."
