The tricky wideman joins the 'Foxes' on a four-year contract for an undisclosed fee, believed to be in the region of £10m.
Ghezzal will fill the gap in the Leicester squad created by compatriot Riyad Mahrez's move to Manchester Cirty earlier this summer.
The 26-year-old began his career with Lyon before joining Monaco on a free last summer.
However, he mustered just two goals in 33 appearances last season, a tally he will be looking to improve upon at the King Power.
Ghezzal becomes Leicester's fifth signing of the summer following the arrivals of Danny Ward, Ricardo Pereira, Jonny Evans and James Maddison and speaking to the club website the Algeria international said he couldn't wait to get started.
"I'm very excited and very happy to be here," said Ghezzal. "I know the coach from Lyon and this is where I want to be.
"It is a good club and an ambitious one too. Leicester City has many great players and I hope we will have a great season."
Leicester boss Claude Puel was similarly delighted, saying: "He is an exciting addition to our group who will bring creativity and competition.
"I know his qualities from my time at Lyon, where he was in the academy, and I look forward to seeing him test himself in the Premier League."
August 5, 2018