Young French sensation scored the first goal in their victory to take the lead and later Valerie Germain wrapped up the title to finish off the game.
Radamel Falcao produced a through ball to Mbappe who made a sprint to snatch the ball and edged past goalkeeper Stephane Ruffier to open the scoring from a tight angle.
The attacker was later got a standing ovation from the supporters during his substitution. It was the 15th goal of the Ligue 1 season for the Europe's most sought out teenager who again showed his class and composure with a superb finish.
After winning four straight titles since 2012-13, the Les Parisiens dream run came to an end from the Leonardo Jardim's side. And now with only one game left to play in the league, Monaco have six points lead over them.
The Monaco boss following their win hailed his team's performance as big as PSG's four straight titles and suggested that it was his biggest achievement in his whole career.
"Winning a Championship in a team that is not a favourite is a great trophy," the boss said in quotes published by L'Equipe.
"This is the most important trophy of my life as a coach. We have worked a lot for 11 months. But the best thing came up with this title. Monaco champion, this is worth four times champion Paris
"It's my biggest achievement. Monaco winning the league is the equivalent of PSG winning it 4 times."
It has been a brilliant season for Jardim's men, as they earned the title in France, as well as gave a good run in all the competitions they competed.
The young squad reached the semi-final stage of the Champions league before knocked-out by Italian giants Juventus.
They also made it to the semi-final of the Coupe de France and final of the Coupe de la Ligue but lost both matches to PSG.
This honour was their first major title after 17 years (1999-2000) and overall club's eight league title. The Champions will make a trip to Rennes in their final match of the campaign on Saturday.