Nils Erik Mattias Bjärsmyr (born 3 January 1986) is a Swedish former professional footballer who played as a centre-back.

After playing for a local club, Grimsås IF, and Husqvarna FF, Bjärsmyr joined IFK Göteborg in 2005.

He became a regular starter later in the year and was nominated best newcomer at the Swedish national football gala.

On 15 July 2009, he signed a four-year contract for Panathinaikos in Super League Greece.

He made his debut in the Sweden national team on 13 January 2008 against Costa Rica.