The award caps a roller-coaster 12 months for the 19-year-old Mbappe, who became just the fourth teenager ever to play in a World Cup final.
And he became just the second teenager ever to score in a final when he scored France's fourth during their 4-2 victory over Croatia.
The award can only be given to players aged 21 or younger so there wasn't too much competition for Mbappe but he was still a worth winner.
Apart from the goal in a victorious final other notable highlights for the PSG forward include tearing Argentina to shreds in the last 16 match when he scored twice and won a penalty.
He follows in the footsteps of international team-mate Paul Pogba who won the award four years ago.