The Hanapepe River is a river on the Hawaiian island of Kauai. It begins at the confluence of the Kō'ula River with the Manuahi Stream and flows generally south, with a total length of 24.2 km (15.0 mi) to its mouth at Hanapepe and Eleele in the Pacific Ocean. The watershed covers an area of 27.7 square miles, draining roughly a twentieth of the island. The name Hanapepe translates to "crushed bay," which may refer to landslides in the area.

Kauaʻi, anglicized as Kauai, is one of the main Hawaiian Islands.