Ostara is one of the eight major holidays, Wiccan sabbats or festivals of the Wheel of the Year, celebrated by largely Wiccan-influenced Neopagan groups. It is celebrated on the Spring Equinox, in the Northern hemisphere around March 21 and in the Southern hemisphere around September 23, depending upon the specific timing of the equinox. Among the Wiccan sabbats, it is preceded by Imbolc and followed by Beltane.

The name is generally not used in British Traditional Wiccan traditions such as Gardnerianism, but Ostara, Eostra or other variants on that name are the most common names for the Sabbat in other modern Pagan witchcraft traditions.

The holiday is a celebration of spring and growth, the renewal of life that appears on the earth after the winter. In the book Eight Sabbats for Witches it is characterized by the rejoining of the Mother Goddess and her lover-consort-son, who spent the winter months in death.

Ostara, according to Jakob Grimm in his Deutsche Mythologie, is the old High German name for the Easter festival. It is a plural; Grimm states that this is because the old festival lasted several days. A rough translation would be 'The Easters'.