The 25-year-old was linked with a move to Manchester United by the British media during the close-season transfer window after he helped England to reach the World Cup semi-finals in Russia for the first time since 1990.
“Ever since I came to this club, I’ve always reiterated how good they’ve been to me,” Maguire told the club website.
“They gave me an opportunity to play in the Premier League and built a great platform for me to go and perform at the World Cup, so I thank them a lot. I owe them a lot and I’m looking forward to the future.”
Maguire played every minute of Leicester’s league campaign last season after signing from Hull City in June last year.
He has also featured in all four of Leicester’s league games so far this season, scoring the winner in a 2-1 victory at Southampton two weeks ago.