The 23-year-old joined Leicester City at the age of eight but enjoyed his first team breakthrough in the 2021/2022 season.
Dewsbury-Hall contributed 28 appearances in the top flight last term, scoring once and assisting two more while he racked up 44 appearances across all competitions.
He has previously spent time on loan at Blackpool and Luton Town.
Speaking to LCFC TV, he said: “I’m so proud and I’m really happy. It’s a great day for myself and my family.
"A lot of hard work has gone into this deal, and it’s a really nice feeling to get it done.
“I have a really good relationship with the Football Club. I’ve been here since I was eight years old, so it was a no-brainer really when I sat down and we spoke about the deal.
"I’ve got big, big ambitions for the future, and I know the Football Club has too.”
Dewsbury-Hall is widely seen as a future Leicester captain and manager Brendan Rodgers has already spoken highly of the Englishman.
When speaking about the 23-year-old earlier this year, the Leicester boss said: "He has the qualities you would look for in an international player: technique, agility, tactical understanding.
"If he can show that consistently over the next few years, he will be on the radar."
Leicester City, who finished eighth last season, begin next season at home to Brentford.
