Marcos Kremer (born 30 July 1997 in Concordia, Entre Ríos, Argentina) is an Argentine rugby union player who plays for the country's Super Rugby team, the Jaguares.
Having played rugby from a young age, representing Los Espinillos at the age of 15 and Club Salto Grande 16, he made his senior debut at Club Atlético del Rosario at the age of 17. He became a familiar starter at the club when he turned 18, starting in most matches in early 2016. In January 2016, he was called up to the Argentina XV side ahead of the 2016 Americas Rugby Championship. He made his senior debut against the United States on 6 February 2016, before even making an appearance at any of the age-grade national teams.
In May 2016, he was called up to the Argentina U20's side for the 2016 World Rugby Under 20 Championship in England. He started in all 5 games at the tournament, helping Los Pumitas to a third placed finish after beating South Africa 49–19 in the bronze final.
After strong performance at the Junior Championship, Kremer was called up to the Jaguares to train with top elite players in Argentina. On 9 July 2016, he made his Super Rugby debut at the age of 18 against New Zealand side the Highlanders.
On 20 July 2016, he was named in Argentina's 33-man squad for the 2016 Rugby Championship by Daniel Hourcade at just the age of 18.