KK Union Olimpija is a basketball team from Slovenia. The club was established in 1946 as a part of a larger sport club Svoboda (Freedom). Later it changed names quite a few times, from Enotnost (1947-1954) (Unity) to AŠK Olimpija (1955-1976), Brest Olimpija (1977-1978), Iskra Olimpija (1979-1982), Smelt Olimpija (1984, 1986-1996), and finally, Union Olimpija (1997-now). The last four names all include names of the main sponsors of the team.

The team played in Tabor gymnasium at the beginning, but moved to Dvorana Tivoli sports arena in 1965. Arena has 4,050 seats. Euroleague matches are played in bigger hall - Ledena dvorana Tivoli (5,500).