Toi moko, or mokomokai, are the preserved heads of Māori, the indigenous people of New Zealand, where the faces have been decorated by tā moko tattooing. They became valuable trade items during the Musket Wars of the early 19th century. Many toi moko were taken from their family and homeland as trophies. Repatriation efforts are underway by Te Papa and Te Herekiekie Haerehuka Herewini to return toi moko to their descendants.

Moko facial tattoos were traditional in Māori culture until about the mid-19th century, when their use began to disappear. There has been something of a revival from the late 20th century. In pre-European Māori culture, they denoted high social status. Generally only men had full facial moko. High-ranked women often had moko on their lips and chins. Moko tattoos served to identify connection between an individual and their ancestors.

Moko marked rites of passage for people of chiefly rank, as well as significant events in their lives. Each moko was unique and contained information about the person's rank, tribe, lineage, occupation and exploits. Moko were expensive to obtain and elaborate moko were usually limited to chiefs and high-ranked warriors. Moreover, the art of moko, the people who created and incised the designs, as well as the moko themselves, were surrounded by strict tapu and protocol.

When someone with moko died, often the head would be preserved. The brain and eyes were removed, with all orifices sealed with flax fibre and gum. The head was then boiled or steamed in an oven before being smoked over an open fire and dried in the sun for several days. It was then treated with shark oil. Such preserved heads, toi moko, would be kept by their families in ornately carved boxes and brought out only for sacred ceremonies.

The heads of enemy chiefs killed in battle were also preserved; these toi moko, being considered trophies of war, would be displayed on the marae and mocked. They were important in diplomatic negotiations between warring tribes, with the return and exchange of mokomokai being a bargaining chip as well as an essential precondition for peace.

Trading these heads with Westerners apparently began with Sir Joseph Banks, the botanist on HMS Endeavour, when he traded old linen drawers (underwear) for the head of a 14-year-old boy. The head was traded as a "curio" and a fascination with the heads began to grow. This continued with mokomokai heads being traded for muskets and the subsequent Musket Wars. During this period of social destabilisation, toi moko became commercial trade items, which could be sold as curios, artworks and museum specimens that fetched high prices in Europe and America, and could be bartered for firearms and ammunition.

The demand for firearms was such that tribes carried out raids on their neighbours to acquire more heads to trade for them. While most early toi moko sold to Europeans were slain warriors, eventually demand from European traders outstripped supply, so the heads of slaves and prisoners were tattooed (though with meaningless motifs rather than genuine moko) in order to provide heads to order.

The peak years of the trade in mokomokai were from 1820 to 1831. On 16 April 1831, Ralph Darling, the Governor of New South Wales, issued a proclamation banning further trade in heads out of New Zealand saying that there was reason to believe that the trade tended to increase the sacrifice of human life. In New Zealand, Maori, concerned that heads were being traded, gradually ceased to preserve them.