The 25-year-old joined Nottingham Forest from boyhood club Liverpool back in 2022, and has become a key part of their squad, making 163 appearances across all competitions.
Williams only signed his previous deal, until 2029, last summer, but following an expectational 2025-26, the club were keen on extending his deal even further.
Forest have now confirmed that the Wales international has signed a new deal, keeping him at the City Ground until the summer of 2030.
Speaking to the club’s website, George Syrianos, Chief Football Officer, said: “Neco has been one of the best players in his position in the Premier League.
“His reliability, consistency and continued determination to improve explain why he has become such a loved player by both his teammates and the supporters.
“We want to continue developing and growing as a club, and a big part of that process is making sure our top-performing players are committed to the club.
“We are delighted he has signed a new deal and look forward to seeing him continue in a Forest shirt."