Lillestrøm SK is a Norwegian football club based in Lillestrøm, Norway. The club is among the country's most successful sides, having won the league five times, and the cup six times. Founded the 2nd of April 1917, LSK already joined the regional league and the Norwegian Cup Championship the same year, and found a lot of success in the regional system of the time.

In 1937–38, the club would join the inaugural eleven-conference top-tier League of Norway, but would face relegation already in its 2nd season. Before the establishment of the League of Norway, winning the cup was considered to be the ultimate glory a Norwegian club could win, and is to this day considered the biggest game in Norway. After World War II and later due to the restructuring of the league-system, Lillestrøm was forced to play in the Third and Second Division. LSK's first major achievements on the national stage would come in the 1950s, after the club secured promotion to the newly established "Main League" in 1952. Throughout the decade, the club established themselves in the top-tier, and reached the cup finale thrice, losing at all three attempts. In 1958-59, the club managed to win their league-group for the first time ever, and would face Fredrikstad FK in the championship final. Fredrikstad had won the league seven times already, were considered the "aristocrats" of Norwegian football, and had gone unbeaten through their group. The clubs fought out a 2–2 tie in the first final, before a rematch was scheduled to months later. This time Lillestrøm won 4–1, and took their first ever major trophy. The two finalists would face each other again already in the final of the following season, this time ending with a 6–2 win for Fredrikstad.

Already in the following season, Lillestrøm would be relegated to the second tier. Despite following up by finishing second in the two following seasons, the clubs would see further misfortune when finishing last in the 1966 season. 1967 would be the weakest season in the clubs history, battling against relegation to the Fourth division. In the third last game of the season, a pivotal 2–1 win at home against Mesna SK helped to secure the spot.

Despite the difficult starting-points, Lillestrøms golden era would come during the 1970s and 80s, with the club climbing from the Third division in 1973, to winning the top-tier First division only three years later in 1976. This was largely due to a new generation of players coming through the academy, spearheaded by the talented striker Tom Lund. During this era, the club would be the first in Norway to bring up the matter of professionalising their players. The 1977 season would be the biggest in the clubs history, when winning the double while facing Dutch giants Ajax in Lillestrøms first ever European Cup-game. This fixture held extra symbolism, as Tom Lund had declined an offer from Ajax in 1973, while still playing in the Norwegian Third division. Despite a promising 2–0 win at Ullevaal Stadion, Ajax would come out victorious with a 4–0 win in Amsterdam.

The club would further go on to win the Norwegian Cup in 1978, 1981, and 1985, and the league in 1986 and 1989. Following this last league-title, the club would go on to almost getting relegated in the following 1990 season, only surviving by beating Bryne and Eik-Tønsberg in the relegation playoff. During the rest of the 1990s, the club would be an established force in the upper half of the league, and was occasionally close to challenging Rosenborg for the titles. 2001 would be the closest the club got to regaining their league title, when at the final day of the season, Lillestrøm remained only one point behind. For taking the title, Lillestrøm would have to beat Tromsø at home, while Brann had to keep Rosenborg to a tie. While Lillestrøm made a promising start, being 2–0 ahead at half-time, what followed was a parachutist flying through the roof over the singing supporters. In need of assistance, the game was 30 minutes delayed, while Rosenborg went on to win 6-2. The 2001 season remains the last time LSK won a medal in the league.

In the following seasons, Lillestrøm would go on to finish seventh three years in a row. In the mid-2000s however, Rosenborgs grip of power finally fell, and a new wave of enthusiasm arrived in Norwegian football. In the 2005, 2006, and 2007 seasons, Lillestrøm would finish 4th at all occasions. The club also made it to the cup final in two of these seasons, losing 4–2 aet in 2005 to Molde, and winning 2–0 in 2007 against Haugesund. The following seasons would turn out disappointing for LSK. Big economic issues lead to weaker results on the pitch, and the club remained almost exclusively in the lower half of the table until eventually getting relegated after a playoff game against Start in 2019. Despite the worsened situation, the club did manage to win the cup in 2017, beating Sarpsborg 08 3–2 in the finale. In a seasons plagued by COVID-19, the club was able to get promoted back up the 1st tier at their first attempt in 2020. Since then, the club has made it to another cup final, and has been playing in Europe again.

For a long time, Lillestrøm held the record for the longest consecutive stay in the top-tier, with their 45 season-stay from 1975 to 2019.

Key Key to league and cup records:

Pld = Matches played W = Matches won D = Matches drawn L = Matches lost GF = Goals for GA = Goals against Pts = Points Pos = Final position NH = Not held GS = Group stage PR = Preliminary Round Q1 = Qualification round 1 Q2 = Qualification round 2 Q3 = Qualification round 3 R1 = Round 1 R2 = Round 2 GS = Group stage R3 = Round 3 QF = Quarter-finals SF = Semi-finals RU = Runners-up W = Winners

ChampionsRunners-upPromotedRelegatedFirst TierSecond TierThird Tier

Kretsserie era (until 1937) SeasonLeagueCupOther Division Tier Pld W D L GF GA Pts Pos 1917Romerike FotballkretsA6510116111stR1–1918Romerike FotballkretsA6501242101st—–1919Romerike FotballkretsA620481243rdR1–1920Romerike FotballkretsA621371153rdR1–1921Romerike FotballkretsA6411131092ndR1–1922Lillestrøm og Omegn FotballkretsA640218982ndR1–1923Lillestrøm og Omegn FotballkretsA5500277101stR3–1924Lillestrøm og Omegn FotballkretsA641116391stR1–1925Lillestrøm og Omegn FotballkretsA321014151stR2–1926Lillestrøm og Omegn FotballkretsA330017361stR1–1927Lillestrøm og Omegn FotballkretsA321014151stR1–1928Lillestrøm og Omegn FotballkretsA6510218111stR2–1929Romerike FotballkretsA129125318111stR2–1930Romerike FotballkretsA7700336141stR4–1931Vestre Romerike FotballkretsA76103810131stR3–1932Vestre Romerike FotballkretsA6510288111stR2–1933Vestre Romerike FotballkretsA77004010141stR3–1934Vestre Romerike FotballkretsA75022611102ndR2–1935Vestre Romerike FotballkretsA6600288121stR2–1936Vestre Romerike FotballkretsA7700325141stR3–1937Pokalserien Gr. 1A330021461stR3Play-OffW

Norgesserien era (1938–1948) SeasonLeagueCupOtherTop goalscorer(s) Division Tier Pld W D L GF GA Pts Pos Player(s) Goals1937-38Norgesserien District II, Gr. A112318203276thQF–Unknown1938-39Norgesserien District II, Gr. A114338253578thR4–Unknown1939-401. divisjon210811438171stR4–Unknown1945Vestre Romerike FotballkretsA111001545201stR4– Alf Martinsen171946-47Vestre Romerike Fotballkrets. 2. divisjon qualifyer.A2017128918352ndR2– Rolf Andresen Knut Bryhn151947-482. divisjon3127322410173rdR2– Rolf Andresen8

Hovedserien era (1948–1962) SeasonLeagueCupOtherTop goalscorer(s) Division Tier Pld W D L GF GA Pts Pos Player(s) Goals1948-492. divisjon31412025117241stR2Promotion Play-OffW Sverre Borgersen171949-502. divisjon2148333014193rdR1– Ivar Wahl181950-511. divisjon Østland-Nordre21411123213232ndR4– Gunnar Lund141951-52Landsdelsserien2149413115221stR2– Gunnar Lund81952-53Hovedserien Gr. B1146442522163rdQF– Sverre Borgersen111953-54Hovedserien Gr. B1148334522193rdRU– Gunnar Arnesen Ivar Wahl141954-55Hovedserien Gr. B1146262730146thQF– Ivar Hansen Gunnar Arnesen121955-56Hovedserien Gr. B1146171925134thRU– Gunnar Arnesen Per Sæther81956-57Hovedserien Gr. B1147252122163rdR2– Per sæther91957-58Hovedserien Gr. B1146173432135thR2– Oddvar Richardsen131958-59Hovedserien Gr. B1149143625191stRUChampionship Play-OffW Oddvar Richardsen141959-60Hovedserien Gr. A1148332821191stR4Championship Play-OffRU Oddvar Richardsen201960-61Hovedserien Gr. B1144372931117thR3– Trond Willadsen81961-62Landsdelsserien Østland Nordre22111556047272ndR4 (1961) R2 (1962)– Oddvar Richardsen28

1. divisjon era (1963–1989) SeasonLeagueCupEuropeOtherTop goalscorer(s) Division Tier Pld W D L GF GA Pts Pos Player(s) Goals19632. divisjon Gr. B2148424126202ndR2–– Oddvar Richardsen1419642. divisjon Gr. B2146262525145thR2–– Per Ytre-Eide1019652. divisjon Gr. A2146172929135thR1–– Jan-Thore Berntzen919662. divisjon Gr. A2141310255658thR3–– Jan-Thore Berntzen919673. divisjon Østland/Nordre3143471930106thR2–– Bjørn Myhre519683. divisjon Østland/Nordre3148152916173rdR1–– Jan-Thore Berntzen Tom Lund919693. divisjon Østland/Nordre31812334218273rdR2–– Tom Lund1619703. divisjon Østland/Nordre3187382326176thR2–– Svein Aardahl919713. divisjon Østland/Nordre3187652517204thR3–– Leif Hansen1319723. divisjon Østland/Nordre31811522813272ndR4–– Tom Lund1219733. divisjon Østland/Nordre31815216711321stQF–– Tom Lund3419742. divisjon Group B2181521448321stR3–– Tom Lund2519751. divisjon12210392720237thR4–– Tom Lund819761. divisjon12213543919311stR3–– Tom Lund1519771. divisjon12216424211361stWEuropean CupR1– Tom Lund1319781. divisjon12211924522302ndWEuropean CupR2– Tom Lund2119791. divisjon1227962523235thQFCup Winners' CupPR– Arne Dokken1119801. divisjon12210753625273rdRU–– Arne Dokken2019811. divisjon12261062625227thW–– Arne Dokken André Krogsæter819821. divisjon12211383526253rdR4Cup Winners' CupR1– Juhani Himanka919831. divisjon12210844028282ndR4–– André Krogsæter1519841. divisjon1228773930235thQFUEFA CupR1– André Krogsæter1719851. divisjon12212823911322ndW–– André Krogsæter1719861. divisjon12216154017331stRUCup Winners' CupR1– Sten Glenn Håberg1519871. divisjon12273+2102221299thR4European CupR2– Sten Glenn Håberg1019881. divisjon12211743818402ndR3–– Jan Åge Fjørtoft1619891. divisjon12216423113521stQFUEFA CupR1– Stein Amundsen10

Tippeligaen era (1990–2016) SeasonLeagueCupEuropeOtherTop goalscorer(s) Division Tier Pld W D L GF GA Pts Pos Player(s) Goals1990Tippeligaen1221141130302510thQFEuropean CupR1Relegation Play-OffW Eivind Arnevåg121991Tippeligaen1229493127315thSF–– Tom Gulbrandsen71992Tippeligaen12211564828384thRU–– Kenneth Nysæther141993Tippeligaen12213364726423rdQFCup Winners' CupR1– Mons Ivar Mjelde291994Tippeligaen12212554223412ndR4UEFA CupR1– Peter Hederman Ståle Solbakken111995Tippeligaen12611875036414thSFUEFA CupR1– Ståle Solbakken201996Tippeligaen12613765433462ndR3Intertoto CupGS– Geir Frigård171997Tippeligaen126951234433210thR4UEFA CupR1– Ståle Solbakken Frank Strandlie91998Tippeligaen12696114149338thR3–– Mamadou Diallo101999Tippeligaen12615386041484thQF–– Heidar Helguson182000Tippeligaen12611784229406thQFUEFA CupR2– Arild Sundgot122001Tippeligaen12617546433562ndQF–– Clayton Zane202002Tippeligaen126106103730367thR3UEFA Champions LeagueQ2– Uwe Rösler92003Tippeligaen12610793335377thR4–– Arild Sundgot92004Tippeligaen12681174533357thSF–– Arild Sundgot192005Tippeligaen12612683731424thRU–– Arild Sundgot152006Tippeligaen12612864433444thQFIntertoto CupR3Royal LeagueRU Robert Koren162007Tippeligaen12612864728444thWUEFA CupQ1Royal LeagueQF Olivier Occean162008Tippeligaen12677123040288thR2UEFA CupQ2– Olivier Occean142009Tippeligaen1309101143503711thR2–– Arild Sundgot112010Tippeligaen130913851444010thR3–– Anthony Ujah172011Tippeligaen130971446523413thR4–– Anthony Ujah132012Tippeligaen13091294647399thR4–– Björn Bergmann Sigurðarson122013Tippeligaen130991237443610thSF–– Petter Vaagan Moen122014Tippeligaen130137104935565thQF–– Petter Vaagan Moen112015Tippeligaen13012994443448thR3–– Fred Friday172016Tippeligaen1308101245503412thR3–– Fred Friday8

Eliteserien era (2017–)