Momo (meaning: crumb) was the 10th king in the Tuʻi Tonga dynasty of Tonga, who lived in the 11th or 12th century CE. He was named after one of the original gods of Tonga, a trio known as Kohai, Koau, mo Momo. The Tuʻi Tonga maritime empire began to expand during his reign.

King Momo had his court in Heketā, near the village of Niutōua (doubly planted coconuttrees). His people were known as the Haʻa-mene-ʻuli (dirty bottoms Clan), because in order to honour him they had to keep their heads lower than his, and thus shuffled around on their bottoms instead of their feet.

One day the king fell in love with a beautiful girl and sent his envoy, Lehaʻuli, to her father, Loʻau, the Tuʻi-Haʻamea (Haʻamea king) with a request for a yam for his plantation. Loʻau understood the real meaning of the request, and responded that he was unable to help as one yam was still immature and the other had already sprouted. He meant that his youngest daughter was still too young while his older daughter, Nua, had already had a child and was therefore an old woman. Her husband was Ngongo kilitoto from Malapo, chief of the Haʻangongo Clan( The clan of Ngongo).

The next day, Momo sent his envoy back to Loʻau with the words: Fena kā ko Nua (sprouted, but still it is Nua), and so Loʻau went to Malapo to ask Ngongokilitoto to give up his wife, which he did. Nua became Momo's wife, and their son became the greatest Tuʻi Tonga of that period, Tuʻitātui. His elder stepbrother, Fasiʻapule, later became a kind of governor.^{[clarification needed]}

The location of Haʻamea is not certain. Some^[who?] claim it was the centre of Tongatapu, near Matangiake, in which case Loʻau was only a minor prince. It is also possible that the name is a variant of Haʻamoa (Samoa), in which case Loʻau was also a powerful king, meaning the marriage story was a mythical way to represent the alliance between Tonga and Samoa, and the start of the empire, although the alliance would only last one generation.

• I.C. Campbell, Classical Tongan kingship, 1989
• E. Bott, Tonga society at the time of Captain Cook's visit, 1982
• ʻO. Māhina, Images from the history and culture of Tonga, 2006