Lillestrøm SK is a football club in Lillestrøm, Akershus county. The club was founded in 1917 and has since then been a part of Norwegian football. Lillestrøm SK has won the league five times and the cup seven times. In 1977, they won both the league and the cup. From 1975 to 2019, Lillestrøm played 45 seasons at the top level of Norwegian football. It is the longest period any club has played at the top level consecutively. Lillestrøm SK also has a women's team that plays in 2.divisjon. The club has many different teams for children and youth, and they also have a group for speed skating. Lillestrøm SK has a partnership with the club LSK Kvinner, which plays in the same colors and uses LSK-hallen for their home games. Lillestrøm SK won the 2025 cup final after beating a strong opponent. It was a big win for the club and their players.