Haaland beat off competition from Barcelona forward Ansu Fati, who was runner-up, to win the award. Bayern Munich's Alphonso Davies came third while Haaland's Dortmund teammate Jadon Sancho took the fourth spot. Rennes' Eduardo Camavinga came in fifth place.
A stellar list of 40 names had been released in October and included Manchester United's Mason Greenwood and United States international Sergino Dest after an impressive breakthrough campaign at Ajax before his move to Barcelona.
The award, handed out by Italian newspaper Tuttosport, honours the best young player in Europe for the calendar year.
Your 2020 Golden Boy Award Winner:— Borussia Dortmund (@BlackYellow) November 21, 2020
⭐️ ERRRRRLIIINNNGG HAAAALAAND ⭐️ pic.twitter.com/hphdKojUtd
Haaland joined Dortmund from FC Salzburg in January after a stunning start to the season in which he scored 28 goals in 22 matches. He scored eight times as the Austrian side crashed out of the Champions League in the group stage.
He scored a hat trick on his Champions League debut as well as goals in each of his first five outings and became the competition's highest-scoring teenager in a single season.
The 20-year-old continued his incredible form with another treble on his Dortmund bow, which helped Lucien Favre's side come from 3-1 down to beat Augsburg 5-3.
Haaland finished the last campaign with 29 goals in all competitions and was sixth in the race for the European Golden Shoe -- level with Messi. He has 11 goals in 11 games for Dortmund in all competitions so far this season.