Kaljaja (Cyrillic: Каљаја) or Kalaja (Albanian) may refer to:
Kaljaja (Balovac) is an archaeological site located southeast of the village of Balovac, in municipality of Podujevo Kaljaja (Teneš Do) is an archaeological site, which is located in Teneš Do, in municipality of Pristina Kaljaja (Binačka) is a fortress located near village Podgrađe, near Gjilan Kaljaja (Bistrička) is the medieval fortress in Prizren Kalaja (Ulcinj)