Melker Hallberg (born 20 October 1995) is a Swedish footballer who plays for Vejle Boldklub as a midfielder.
Hallberg grew up in the small town of Ljungbyholm, shortly to the south of Kalmar. There he started with the local club Möre BK where he played for the first team in the seventh tier of Swedish football at age thirteen.
In 2010 Hallberg was brought into the Kalmar FF youth section. Two years later he became the youngest-ever first-team player for the club when he made his Allsvenskan debut at the age of sixteen. On July 15, 2012, Hallberg became the fourth-youngest Allsvenskan goalscorer of all time when he scored the game-winning 2–1 goal against IF Elfsborg. In December 2012 he signed a new four-year contract extension. After his second season in Allsvenskan as a seventeen-year-old, Hallberg was ranked as the 14th-best player in the league by newspaper Expressen.
In August 2014, Hallberg signed for Italian club Udinese. He made his debut in January 2015.
In 2015, he was loaned out to Norwegian club Vålerenga Fotball, and in 2016 he was loaned out to Hammarby Fotboll in his native Sweden.
Hallberg has featured regularly at all age levels of Swedish youth national teams. In August 2013 he got selected for the first time ever to the Swedish U21 squad in a friendly against Norway.