The Portugal international has been rewarded with improved terms after establishing himself as an important part of the club's plans. His previous agreement was due to expire in 2031.
Neto, 26, joined Chelsea from Wolves in 2024 for a reported 51.4 million pounds and has since become a regular in the squad. He has made 108 appearances for the club, scoring 21 goals, while helping Chelsea win the UEFA Conference League and FIFA Club World Cup.
"This is an unbelievable moment," Neto told Chelsea's official website.
"From when I arrived, I have always felt like the people here helped me a lot. I feel like home here, I feel like I want to achieve more things here.
"I have had some good moments here as a group and as an individual, and now I want to have more of those moments. I'm really excited because I think we can achieve a lot of things together."
The new agreement comes after Neto was linked with a possible departure during the most recent transfer window, with Manchester City among the clubs reportedly monitoring his situation. Chelsea, however, have now made clear that he remains central to their long-term project.
Blues boss Xabi Alonso has also made his appreciation of Neto's qualities clear, praising his ability to beat opponents one-on-one, contribute goals and work hard without the ball.
Alonso also highlighted the winger's ability to press high, attack the last line and combine effectively with his teammates in a system based around quick transitions.
"For me, he's a winger. You can call him winger, wing-back, because he has many qualities," said the Spanish tactician.
"He can play on the last line and defend on the first line. He has this capacity to do many things.
"He's good one-vs-one, he's scoring goals, he has a fantastic work-rate. He connects well with the players around him.
"I knew him well from watching many games from Chelsea, but with him, you know he's going to compete.
"You want these players in your team. Very happy with the work he is doing."
Neto has made five appearances in all competitions this season, scoring twice, and has started two of Chelsea's three Premier League matches under Alonso.
The extension is the latest in a series of contract renewals for key Chelsea players, following fresh deals for Joao Pedro, Reece James and Moises Caicedo.