The Norway international has been one of Arsenal's best players in the last few years.
Odegaard has found a permanent home in North London after spending loan spells at Heerenveen, Vitesse and Real Sociedad while on the books of Real Madrid, whom he joined in 2015.
Odegaard joined Arsenal initially on loan from Real Madrid in January 2021 and the move was made permanent for £30m at the start of the 2021/2022 season.
The 24-year-old was named Arsenal captain at the start of last season and played an instrumental role in their second place finish in the Premier League and return to the Champions League for the first time since the 2016/2017 season.
Odegaard has made 112 appearances for Arsenal, scoring 27 goals and laying on 15 assists.
“Signing a new contract was a really easy decision for me for lots of reasons," Odegaard told the club's website in an official statement.
"Mainly what we are doing right now as a club is special, and I want to be a part of that. I’m really excited for what’s to come here. I’ve found a place where I can be really settled and call my home.
"My story is a bit different maybe, as I moved around different clubs since I was 16. At Arsenal, since the first day, I’ve felt great and this is definitely my home now.
"I just want to say thanks to everyone working at the club and of course, our fantastic supporters. I will continue to give everything to bring success to this club in the years to come.”
Manager Mikel Arteta added: "Martin signing a new long-term contract is such good news for everyone connected with Arsenal. He is our captain and a hugely respected person at our club, who is a great role model and professional, bringing quality and maturity in everything he does. On the pitch, as everyone has seen, Martin is a young player of top quality who consistently contributes at a such a high level.
"As a manager, working with Martin the person and the player is an absolute joy, and it’s great that after experiencing a number of clubs already in his career, he is now settled and really feels at home at Arsenal. We all look forward to continuing our journey with Martin in the years to come.”