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)

• Brachymasicera
• Brachymenes
• Brachymera
• Brachymeryx
• Brachymesia
• Brachymetatarsia
• Brachymyrmex
• Brachymystax
• Brachymystax lenok
• Brachymystus
• Brachynota
• Brachyodont
• Brachyona
• Brachyonychia
• Brachyopa
• Brachyopidae
• Brachyopini
• Brachyopoidea
• Brachyopomorpha
• Brachyopterus
• Brachyosaurus
• Brachypalpoides
• Brachypalpus
• Brachypareion
• Brachypelma albopilosum