Kaliya (IAST: Kāliya, Devanagari: कालिय), in Hindu traditions, was a venomous Nāga living in the Yamunā river, in Vṛndāvana.

The story of Krishna and Kāliya is told in the sixteenth chapter of the Tenth Canto of the Bhagavata Purana.

The proper home of Kāliya was the island of Ramaṇaka, but he had been driven away from there in fear of Garuḍa, the foe of all serpents.

Meanwhile, Kāliya attempted to escape, but Krishna stomped on his tail and warned him to not trouble anyone again before returning to the people.

Krishna immediately regained his original form and began to jump on all of Kāliya's heads so as to release the poison in the snake so that he could no longer pollute the Yamunā.

Krishna suddenly sprang onto Kāliya's head and assumed the weight of the whole universe, beating him with his feet.

The people who had gathered on the banks of Yamunā were terrified, beholding the water that had changed to a poison colour.