The trainer joins the principality club after a successful season with Sporting Lisbon, which he led to second in the Primeira Liga.
Jardim will begin taking training with his new players, who came second in Ligue 1 in 2013-14, on June 30.
"I am very happy to work at Monaco because it is a great club," the 39-year-old told Monaco TV. "I thought very hard about this project and I think we'll do a good job with the whole group.
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"AS Monaco is a team with quality players. There are a lot of talented young players. I'll do everything [I can] to bring it forward.
"The first thing [I have to do] is to learn to speak French. I have been taking lessons for a few days. It is a question of respect for the fans, the people of the club and Ligue 1," he added.
Jardim joins Monaco after a successful season with Sporting Lisbon, during which he led the club to second place in the Primeira Liga.