Ruja was one of the foremost Estonian rock bands of the 1970s and 1980s. The name of the band comes from a neologism "ruja", for science fiction, though there are people who believe that "ruja" is actually made up of the first letters of the band's important members (R – Rein Rannap, U – Urmas Alender, J – Jaanus Nõgisto and A – Andrus Vaht). The band released their first and self-titled album in 1979. Many of the original melodies of Ruja were composed by Rein Rannap.

The band was created by Rein Rannap in 1971 while in the 11th grade. Ruja's 3 first members were Rein Rannap, Urmas Alender and Andrus Vaht.

On September 28, 1994, the band's lead singer, Urmas Alender, died in the sinking of passenger ferry M/S Estonia. After Alender's funeral concert a couple of days later, the remaining members of the band decided never to perform under the name of "Ruja" again.