The 28-year-old, who joined the Magpies from Leicester City in July 2023, still had two years remaining on his previous five-year deal but has now extended his stay at St James' Park following an impressive campaign.
Barnes enjoyed one of the best seasons of his Newcastle career in 2025-26, contributing 16 goals and six assists in 57 appearances across all competitions. His overall record for the club now stands at 30 goals in 120 matches, while his performances also earned him a return to the England squad under Thomas Tuchel for the first time in almost six years.
The new deal also comes after speculation linking Barnes with Aston Villa, while Newcastle have been working to maintain stability in their squad following Anthony Gordon's move to Barcelona and Sandro Tonali's transfer to Tottenham. The club are also keen to fend off Arsenal's reported interest in captain Bruno Guimaraes.
Barnes said he was delighted to commit his future to the club.
"It feels great to sign this new contract before the new season starts. It has been an amazing journey so far and I'm delighted to continue that.
"When I first joined the club I quickly learned what a special place it is, but after three years here I know that even more now. I love everything about it here - the city, the stadium and the people.
"I've had a taste of success in the last few years and enjoyed some really special moments with this team. We all want more of that, and I want to be a key player that helps push this club forward."
Head coach Eddie Howe praised Barnes' contribution since arriving on Tyneside and believes there is even more to come from the England international.
"Harvey's new contract is very well deserved and reflects the work he has put in and the quality he has shown throughout his time at Newcastle," Howe said.
"He has consistently produced special moments at vital times for the team. He is calm in front of goal, whether in one-on-one situations or shooting from distance, and he is always a threat from wide areas.
"He has vast experience at the highest level, but we believe there is still more to come."
Newcastle manager Eddie Howe admits he cannot guarantee Bruno Guimaraes will remain at St James' Park amid mounting speculation linking the club captain with a move to Arsenal.
Andoni Iraola's first match as Liverpool head coach ended in victory, but the Spaniard admitted Joe Gomez's early injury overshadowed the Reds' 4-2 pre-season win over Sunderland in Nashville.
Newcastle United have completed the signing of midfielder Aladji Bamba from French club AS Monaco on a five-year contract, the Premier League club confirmed on Friday.
Arsenal have confirmed that William Saliba will be sidelined for an "extended period" after suffering a back injury during France's World Cup campaign, although the defender will not require surgery.
