In Hindu traditions, Kalki is the tenth and final Maha Avatara (great incarnation) of Vishnu the Preserver, who will come to end the Kali Yuga, (The Age of Darkness and Destruction). The name Kalki is often a metaphor for "Eternity" or "Time". The origins of the name probably lie in the word Kalka which refers to "dirt", "filth" or "foulness" and hence denotes the "Destroyer of Foulness", "Destroyer of Confusion", "Destroyer of Darkness", or "The Annihilator of Ignorance". Other similar and divergent interpretations based on varying etymological derivations from the ancient Sanskrit language, including one simply meaning "White Horse", have been made.

In the Buddhist Kalachakra tradition, some 25 rulers of the legendary Shambhala Kingdom have the title of Kalki, Kulika or Kali-king.