The Kaituna River is in the Bay of Plenty region of the North Island of New Zealand. It is the outflow from Lakes Rotorua and Rotoiti, and flows northwards for 45 kilometres (28 mi), emptying into the Bay of Plenty at Maketu. It was the subject of a claim concerning the effluent flowing down the river from Lake Rotorua, which resulted in movement to a land treatment system.

The New Zealand Ministry for Culture and Heritage gives a translation of "eat eels" for Kaituna.

The upper section of the Kaituna, also referred to as Okere River, offers some of the best whitewater kayaking and rafting in the world, with the Okere Falls area containing the highest commercially rafted waterfall, 7 metres (23 ft), in the world. It is also famous for its trout fishing.

Kaituna River flows north from the Ōkere Inlet of Lake Rotoiti, the location of Okere Falls, a small settlement on the lake. This section of the river is referred to as the Ōkere River by locals. Notable waterfalls in the upper gorge are Okere Falls, Tutea Falls (the highest commercially rafted waterfall), and Trout Pool Falls, all of which are accessible via the Okere Falls track.^{[citation needed]} The river is joined by numerous tributaries, including the Paraiti River, Raparapahoe Canal and Kopuaroa Canal.

The majority of the river empties into the Bay of Plenty via the Te Tumu Cut, a man-made channel constructed in 1956. Smaller amounts of water flow into the former natural mouth of the river, the Maketu Estuary, via the Papahikawai Channel, and a man made channel called Ford's Cut. The Kaituna River historically bypassed the Maketu Estuary during times of high flooding, flowing directly into the Bay of Plenty near the modern Te Tumu Cut once every 30-50 years.

The river has traditional significance in Māori culture, especially to Te Arawa-affiliated iwi and hapū. Traditional stories describe the Arawa migratory waka visiting the river catchment, and finding small communities already living in the area. The descendants of the ancestors Ngātoro-i-rangi, Tama-te-kapua, Tia and Hei settled in the river catchment, establishing kāinga and fortified pā. Modern iwi and hapū, who trace their lineage to these ancestors, include Tapuika, Waitaha, Ngāti Rangiwewehi, Ngāti Pikiao and Ngāti Whakaue. The river is an important traditional resource, and was used for fishing, with the riperian edges used to grow crops, including kūmara, and the harvesting of harakeke (flax). The name of the river refers to eels being a major food resource.

In 1879, early European settlers petitioned the government for 3,000 acres (1,200 ha) of land at Te Puke, and established a flax industry along the Kaituna River shores. The river became a major transportation route between Te Puke and Tauranga in the latter 19th century. In 1881, snags were removed from the river to allow river boats to run between Canaan Landing, near Te Puke, and the river port at Maketu from May 1881, until Northern Steamship closed its office on 29 September 1917.

The Okere Falls Power Station was established at the source of the river in 1901, as the first generating plant built by the New Zealand government. Several proposals for a larger power station have been considered, but the high cost of those projects has meant that none have been built to date. The power station operated until 1936.