IK Sirius Fotboll
|Full name||Idrottsklubben Sirius|
|Head coach||Kim Bergstrand|
|2013||Division 1 Norra, 1st (Promoted)|
The club was formed in 1907, with its first success coming in 1924 when they reached the Svenska Mästerskapet final (not to be confused with Svenska Serien, which never acquired an official status of deciding the Swedish Champions). In the final, they were trounced 5-0 by Fässbergs IF.
The Allsvenskan years
The club spent the next forty years in lower division anonymity, before favourable economic circumstances enabled them to gain promotion to Allsvenskan in 1968, although they were relegated after just one season. The club's high point was arguably in the years 1973-1974, when the club again gained promotion to the highest league and its squad contained a number of high-profile players, such as Roland Grip, then a member of the Swedish national team.
Obscurity and comeback
After the club's relegation from Allsvenskan in 1974, the club played in the second division until they plummeted to fourth division level following a couple of hard years in the beginning of the 1980s. The 1990s were mostly spent at a second tier level, i.e. the old Division 1, corresponding to the modern Superettan. The club then played the first five years of the 21st century in Division 2, before returning to Division 1 in 2006 (although still playing at a third tier level).
With new manager Magnus Pehrsson and prodigal son and goal-getter Olle Kullinger (starting his career with IF VP and later also having played with Enköpings SK, Halmstads BK and IF Brommapojkarna in Superettan and Allsvenskan) bearing the captaincy, the club finished the season in second place, which meant they had to qualify in order to gain promotion to Superettan. IK Sirius played the first leg at home against Väsby United on 25 October. Due to some seriously poor defending, Väsby were able to go 1-0 up just before the half-time break. Sirius recovered slightly in the second period, and were able to equalise in the 83rd minute. In the second leg, in front of about 1000 travelling fans, Sirius were completely dominant but also rather wasteful with their chances. They managed, however to break the deadlock in the 73rd minute, Olle Kullinger managing to knock a rebound past the Väsby keeper. With the aggregate score of 2-1, Sirius celebrated their 100th anniversary in the Superettan, much to the delight of their fans.
Magnus Pehrsson resigned as manager and Pär Millqvist was appointed and brought in Gary Sundgren as his assistant manager. After a strong first half of the season the club finished 7th in Superettan 2007. The team struggled through most of the 2008-season but finally finished 12:th and avoided relegation. Millqvist and Sundgren was sacked after the first six games and youth-team coaches Johan Mattsson and Andreas Brännström lead the team for the rest of the season.
In preparation for the 2009 season they appointed Jens T Andersson from Väsby and AIK as new manager. Like the season before they struggled in the bottom of the league and with just five games left to play of the season Jens T Andersson resigned as manager due to the lack of good results. Assistant coach Andreas Brännström were once again hired as new head manager but this time he could not save the team from degradation.
In 2010 IK Sirius played in the third tier Division 1 Norra and finished 2nd in the table 5 points behind rivals Västerås SK and as a result they went trough to the Superettan play-offs, where they went head-to-head with Jönköpings Södra. After a 0-1 defeat at home they lost the away game with 3-0 and faced another season in Division 1 Norra.
2011 the team was voted by all the managers of the league as favourites to win but failed to live up to the expectations. They finished 3rd in Division 1 Norra, just 2 points from finishing first and goal-difference kept them from the second spot which leads to Superettan play-offs. As a result coach Andreas Brännström and his assistant Antonio Andric was forced to leave the club after the season.
Season to season
* League restructuring in 2006 resulted in a new division being created at Tier 3 and subsequent divisions dropping a level. 
- As of 22 January 2014
Note: Flags indicate national team as has been defined under FIFA eligibility rules. Players may hold more than one non-FIFA nationality.
For season transfers, see transfers winter 2013–14.
The following players are either listed on the official IK Sirius website or have represented their national team.
- As of 16 November 2013
In recent seasons IK Sirius FK have had the following average attendances:
* Attendances are provided in the Publikliga sections of the Svenska Fotbollförbundet website. 
- Svenska Mästerskapet:
- Runners-up (1): 1924
- Division 1 Norra:
- Winners (1): 2013
- Runners-up (2): 2006, 2010
- Division 2 Östra Svealand:
- Winners (1): 1997
- "Kontaktuppgifter och tävlingar – Upplands Fotbollförbund - Svenskfotboll.se". Retrieved 2011-01-13.
- "GAIS - Lagfacta - IK Sirius". Retrieved 05.09.2010.
- "A-laget" (in Swedish). IK Sirius Fotboll. Retrieved 16 November 2013.
- "Kultspelarna - siriuspublikens egna favoriter". Retrieved 2013-11-09.
- "Kontaktuppgifter och tävlingar - Svenska Fotbollförbundet - svenskfotboll.se". Retrieved 2010-12-09.