Wairangi was a Māori rangatira (chieftain) of the Ngāti Takihiku hapū of the Ngāti Raukawa iwi in the Tainui tribal confederation from the Waikato region, New Zealand and the ancestor of the Ngāti Wairangi hapū. He probably lived in the mid-seventeenth century.

Wairangi was a son of Takihiku and brother of Tama-te-hura, Upoko-iti, and Pipito. His grandfather Raukawa, son of Tūrongo and Māhina-a-rangi, was the founder of Ngāti Raukawa and a direct descendant of Hoturoa, the captain of the Tainui.

Wairangi joined Whāita in his war against Ngāti Kahu-pungapunga, in which they eliminated Ngāti Kahu-pungapunga and seized the upper reaches of the Waikato River, between Putāruru and Ātiamuri. After the initial assault on the Ngāti Kahu-pungapunga settlements south of Maungatautari, Wairangi and Upoko-iti led half of the war party south on the west side of the Waikato River. They passed Te Wawa, killed the rangatira Whakahi at Te Pae-o-Turawau, and killed Korouamaku at Te Ngautuku, near Ātiamuri.

The last of the Ngāti Kahu-pungapunga made their stand at Pōhatu-roa, a hill just west of Ātiamuri, which was the base of their allies, the Ngāti Hotu. Whāita and Wairangi's war-parties reunited and surrounded the hill. The two forces clashed repeatedly, but eventually hunger sapped the defenders' strength and they were unable to deflect the Ngāti Raukawa assault, which captured the chieftain Hikaraupi and the mountain.

After this, Wairangi settled the portion of Ngāti Kahu-pungapunga's lands south of Whakamaru, making his base at Ruru-nui, near Whare-puhanga. His descendants, Ngāti Wairangi, still live in the area and now share Mōkai marae with a number of other hapū.

While Wairangi was out hunting birds at Kāwhia, Ruru-nui was visited by Tupeteka, a rangatira of Ngāti Maru from Te Āea in the Waihou River valley near Te Aroha. Wairangi's wife Parewhete had sex with him and Wairangi realised this because when he returned the food that Parewhete served him was not properly cooked, or because his other wife, Puroku had noticed some of Parewhete's kokowai rouge on Tupeteka's cheek. Therefore, he beat her and she fled to Tupeteka's village.

During this flight, Parewhete painted some of her kokowai on a mānuka tree at a place now called Mānuka-tutahi (mānuka flowers are usually white, but sometimes pink or red). She left one of her cloaks at Āniwaniwa, where she crossed the Waikato. A red cliff face by the Waikato River or at Pari-kararangaranga near Matamata is said to derive from this flight, either because when Parewhete stopped to wash she left her maro ('skirt') on the rock and the blood from her menstruation turned it red, or because she painted more kokowai on the cliff. These traces allowed people from Ruru-nui to work out that Parewhete had gone to Te Āea.

When Tupeteka refused to return Parewhete, Wairangi gathered a war-party of 140 men along with his brothers Tama-te-hura, Upoko-iti, and Pipito. When they arrived at Te Āea, they were welcomed into the village and performed the tangi ('ceremonial weeping') on the marae. They were let into a giant wharau guesthouse. According to Te Rangi Hīroa his suspicions were aroused by the fact that the posts of the wharau were made of whole trunks of kahikatea - far sturdier than required for construction. Meanwhile, Tupeteka summoned a war-party of Ngāti Maru from the Hauraki Gulf.