Kjelsas Fotball is the association football section of the sports club Kjelsas IL, based in the Kjelsas/Grefsen area of Oslo, Norway. The club was founded in 1913. It currently plays in the 2. divisjon, having been relegated from the 1. divisjon in 2001.
Kjelsas played play-off against Kongsvinger to earn promotion to Tippeligaen in 1998, but lost 7–2 on aggregate. On 11 May 2011, Kjelsas eliminated the top-tier team Valerenga in the second round of the 2011 Norwegian Cup.
Kjelsas Fotball had 1370 players (of these about 460 female) registered in 2019, divided in 55 teams.