Tuvaluan mythology tells stories of the creation of the islands of Tuvalu and of the founding ancestors of each island. While on some of the islands there are stories of spirits creating the islands, a creation story that is found on many of the islands is that te Pusi mo te Ali (the Eel and the Flounder) created the islands of Tuvalu; te Ali (the flounder) is believed to be the origin of the flat atolls of Tuvalu and te Pusi (the eel) is the model for the coconut palms that are important in the lives of Tuvaluans. The strength of this belief has the consequence that Moray eel are tapu and are not eaten.
The reef islands and atolls of Tuvalu are identified as being part of West Polynesia. During pre-European-contact times there was frequent canoe voyaging between the islands as Polynesian navigation skills are recognised to have allowed deliberate journeys on double-hulled sailing canoes or outrigger canoes. The pattern of settlement that is believed to have occurred is that the Polynesians spread out from Tonga and the Samoan Islands into the Tuvaluan atolls. The distinct linguistic areas that have been recognised in the islands of Tuvalu shows that the Tongan influence is stronger in the northern islands of Nanumea and Nanumaga rather than in the south.: 15
The stories as to the ancestors of the Tuvaluans vary from island to island. On some of the islands there are stories of spirits creating the island, however a creation story that is found on many of the islands is that te Pusi mo te Ali (the Eel and the Flounder) created the islands of Tuvalu.
The voyaging ancestors brought the myths from their islands of origin, with these stories being adapted to over time to become the mythology of Tuvalu. Each island has stories as to the origins of their ancestors. On Funafuti and Vaitupu the founding ancestor is described as being as Telematua (or Telemaiatua), a giant from Samoa;: 15–16  whereas on Nukufetau the ancestors are described as being from Tonga.
On Nanumea the founding ancestor is described as being from Tonga, although Nanumea also has links to Tokelau.: 15–16 The ancestor of the people of Nanumea is described as Tefolaha, who was part human, part spirit from Tonga; on Nanumaga the founding ancestor is described as Tepuhi, a spirit with the shape of a sea-serpent, who came originally from Fiji, although there are other creation stories that are told on Nanumaga that have links to Tonga and Samoa.
The creation story told on Nui describes a group of spirits raising the eleven islets of Nui from the ocean floor and the ancestors arrived from Samoa on a canoe named Vakatiumalie. The captain of the canoe was Peau, a man from Manono Island in Samoa.
On Niutao the understanding is that their ancestors came from Samoa in the 12th or 13th century. Niutaon mythology tells the story of the people who first inhabited the island: “The first inhabitants of Niutao were half spirit and half human beings who lived at Mulitefao. Their leader was Kulu who took the form of a woman. The first human settlers came from Samoa in a canoe captained by a man called Mataika. He settled at Tamana on the eastern side of the island, where winds swept the spray of the surf over the reef.”
In 1896 Professor Professor William Sollas went to Funafuti as the leader of the Funafuti Coral Reef Boring Expedition of the Royal Society; Prof. Sollas subsequently published The Legendary History of Funafuti, an oral history given by Erivara, the chief of Funafuti, through the trader Jack O’Brien (as translator), which began:
When Tefolaha arrived on Nanumea he found two women named Pai and Vau. Tefolaha ordered them to leave as he claimed the island. Pai and Vau replied that he should leave unless he could tell them their names. This is a defence that appears in other mythologies of the Pacific that possibly reflects the belief that to know a person's name is to have some power over that person. Tefolaha knew their names so they departed. As they left, sand spilled out of their baskets creating the smaller islets of Nanumea.
There are some stories that are shared by all the islands of Tuvalu. An important creation myth of the islands of Tuvalu is the story of te Pusi mo te Ali (the Eel and the Flounder). The story of te Pusi mo te Ali is told by Talakatoa O’Brien in Tuvalu: A History.: 13–15  The essence of the story is that the Eel and the Flounder were once great friends. One day they decided to carry a huge stone to test who was the stronger. They began to argue and then to fight. As they fought the Flounder was crushed flat beneath the stone. The Flounder became free and chased the Eel who was vomiting after getting a heavy blow to his stomach. The Eel became thinner and thinner until the Eel could hide in a hole. The Eel said some magic words as protection from the Flounder:
The Flounder's flat body became the model for the atolls of Tuvalu. The Eel's thin round body became the model for the coconut palm. After the Flounder died the Eel threw the stone in the air and said the magic words:
By repeatedly throwing the stone in the air the Eel created night and day, the blue sky and the sea. The Eel then broke the stone into eight pieces to create the main islands of Tuvalu.: 13–15 The name, Tuvalu, means "eight standing together" in Tuvaluan.
The story of te Pusi mo te Ali can be compared to the story of Sina and the Eel from Samoan mythology, which also explains the origins of the first coconut tree.