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.

Fjolnir - naised on Islandi naiskondade jalgpalliklubi, mis tegutseb Reykjavíkis. Klubi asutati 2001. aastal ja on sellest ajast alates mänginud Islandi kõrgliigas. Fjolnir on võitnud Islandi karika kolm korda (2013, 2016, 2018) ja Superkarika kaks korda (2014, 2019). Klubi on osalenud ka UEFA Naiste Meistrite Liigas mitu korda.