Karnaphuli (also spelt Karnafuli) is a river in the south-eastern part of Bangladesh. Originating from the Lushai hills in Mizoram, India, it flows through Chittagong Hill Tracts and Chittagong into the Bay of Bengal. A large hydroelectric power plant using Karnaphuli river was built at Kaptai during the 1960s. The mouth of the river hosts Chittagong sea port, the main port of Bangladesh.

Legend has it that a princess from neighboring Arakan (now in Myanmar) fell in love with a tribal prince of Chittagong. The lovers were once enjoying a moonlit boatride on the river. While admiring the reflection of the moon dancing on the rippled water surface, the princess leaned slightly and a flower tucked in the hair over her ear by the prince suddenly fell into the river. The princess was grief-stricken at losing the flower, which she held very dear as a present from her charming prince. She immediately jumped into the river to retrieve the flower but could not. Instead she was carried away by the fast-flowing current and vanished in the river. The prince dived into the river to rescue the princess but in vain. Out of sorrow he drowned himself in the river to unite with the princess after death. This tragedy gave the river its name Karnafuli from the word 'karnaphul' meaning 'flower adorning the ear'. The river is known to the Marma tribe as the Kynsa Khyong.