Mathias Rundgreen (born 21 February 1991) is a Norwegian cross-country skier.

He competed in three events at the 2011 Junior World Championships, winning a gold medal in the relay.

He later competed at the 2012, 2013 and 2014 Junior World Championships, all in the U23 age class, and took a bronze medal in the 2014 15 km.

He broke the top 10 and 20 at the same time with a seventh place in the March 2015 Lahti sprint.

He made the podium for the first time in February 2017 in PyeongChang, finishing third in the 15+15 km skiathlon.