Ishtar was held to be the great Mother Goddess in ancient Assyrian and Bablyonian mythology. It was believed she was the daughter of the sky-god, Anu, or the moon god, Sin. Gradually over time, she absorbed characteristics of various goddesses and represented various aspects. Her worship spread throughout the Middle East, Greece, and Egypt. She was an oracle, governed over sex and war, and protected men from evil. As the many-breasted Opener of the Womb, she was the giver of all life; as the Destroyer and Queen of the Underworld, she also was the taker of all life. As the moon goddess, her waxing and waning governed the cyclical birth and death of the planet. She was the Heavenly Cow, the Green One, and the Mistress of the Field.

As a war goddess Ishtar was specially honored in Assyria. She was depicted as carrying a bow and quiver, her warlike aspect receiving emphasis with a beard similar to the god Ashur. Inscriptions state that Ishtar was party to choosing of the king. Ashur-natsir-pala II (884-860 BC), so certain of the divine election, was the monarch renowned for his cruelty toward rebels and enemies. He orders of skinning captives live or cutting off their hands became accepted policy.

Her son Tammuz, also called the Green One, became her lover when reaching manhood. Ishtar descended into the realm of the dead to rescue Tammuz; a myth similar to those of Inanna and Damuzi, and Demeter and Kore. When Ishtaer descended into the underworld she appeared as a hostile and threatening figure; death overcame her while there, which caused fertility and sexual desire to become dormant, and await her seasonal return.

An Akkadian fragment describes the wailing of Ishtar for Tammuz, whose annual death, resurrection, and marriage strongly indicate a fertility ritual connected to an agricultural cycle. His worship spread into Canaan, where Ezekiel complained that even at "the door of the gate of the Lord's house…there sat women weeping for Tammuz."

As Queen of Heaven, she replaced Sin as the moon deity; she rode through the sky at night in a chariot drawn by goats or lions. The zodiac was known as the "girdle of Ishtar," which also refers to the ancient moon calendar. In this position she was the giver of omens, and prophecy through dreams, and through her magic, others could obtain secret knowledge.

Ishtar was associated with the planet Venus. Both the lion and dove were sacred to her