Ungmennafélagið Fjölnir, commonly known as Fjölnir, is a multi-sport club from Iceland. The club is located in Grafarvogur, Reykjavík. The club was founded in 1988 under the original name Ungmennafélagið Grafarvogur; however, because another team already had the abbreviation UMFG, the name was changed to Ungmennafélagið Fjölnir, commonly referred to as Fjölnir. A total of nine sports are practised at the club: football, basketball, handball, taekwondo, karate, tennis, swimming, athletics and gymnastics. Chess is also played at the club. Each one of these sports has their own department with their own board but all are under the main board and the club office.

Fjölnir damer är ett isländskt fotbollslag som spelar i Úrvalsdeild kvenna, den högsta divisionen i isländsk damfotboll. Laget har base i Reykjavik och spelar sina hemmamatcher på KR-völlur.

Fjölnir damer grundades 1969 och har vunnit det isländska mästerskapet nio gånger, senast 2019. Laget har även vunnit den isländska cupen sex gånger, senast 2018.

I Champions League har Fjölnir damer nått gruppspelet fyra gånger, 2010/11, 2011/12, 2013/14 och 2019/20.