90 may refer to:

90 (number)

one of the years 90 BC, AD 90, 1990, 2090, etc.

90 (album), an album by the electronic music group 808 State

90 (EP), an album by the band South Club

Atomic number 90: thorium

Audi 90, a precursor of the Audi A4 automobile

Saab 90, a compact executive car