Ketu may refer to:
Ketu is a historical region in what is now the Republic of Benin, in the area of the town of Kétou (Ketu). It is one of the oldest capitals of the Yoruba speaking people, tracing its establishment to a settlement founded by a daughter of Oduduwa, also known as Odudua, Oòdua and Eleduwa. The regents of the town were traditionally styled "Alaketu", and are believed to be related to the Egba sub-group of the Yoruba people in present-day Nigeria.
Ketu is considered one of the seven original kingdoms established by the children of Oduduwa in Oyo mythic history, though this ancient pedigree has been somewhat neglected in contemporary Yoruba historical research, which tends to focus on communities within Nigeria. The exact status of Ketu within the Oyo empire however is contested. Oyo sources claim Ketu as a dependency with claims that the Ketu paid an annual tribute and that its ruler attended the Bere festival in Oyo. In any case, there is no doubt that Ketu and Oyo maintained friendly relations largely due to their historical, linguistic, cultural and ethnic ties.
Ketu (Sanskrit: केतु, IAST: Ketú) () is the descending lunar node in Vedic, or Hindu astrology. After the head of Svarbhānu, an Asura, was cut off by God Vishnu, his head and body joined with a snake to form 'Ketu', representing the body without a head, and Rahu, representing the head without a body. According to some accounts in Hindu mythology, Ketu belongs to Jaimini Gotra, whereas Rahu is from Paiteenasa gotra and hence both are totally different entities with distinct characteristics and not two parts of a common body. Ketu is generally referred to as a "shadow" planet. It is believed to have a tremendous impact on human lives and also the whole creation. In some special circumstances it helps someone achieve the zenith of fame. Ketu is often depicted with a gem or star on his head signifying a mystery light.
Astronomically, Rahu and Ketu denote the points of intersection of the paths of the Sun and the Moon as they move on the celestial sphere. Therefore, Rahu and Ketu are respectively called the north and the south lunar nodes. The fact that eclipses occur when the Sun and the Moon are at one of these points gives rise to the understanding of swallowing of the Sun and the Moon by the snake.