In Etruscan religion and mythology, Thesan is the Etruscan goddess of the dawn. Thesan is the Roman equivalent of Aurora. In Etruria, she received offerings together with the sun god Usil as described in the liber linteus. She was especially worshipped at Caere's harbour of Pyrgi, where a temple was dedicated to her and a singular series of "daybreak antefixes" was excavated.

Thesan was depicted with wings and sometimes nude, such as a clay acroterium from Astrone valley. According to scholar De Grummond: "Although Thesan is often compared with the Greek Eos and the Roman Aurora, Greek texts suggest that they understood her cult persona at Pyrgi to be rather a counterpart of Leukothea, the “White Goddess,” who had a special connection with the sea, and who in turn was assimilated to the Roman Mater Matuta, a goddess of the morning and of childbirth."

Unlike Eos in the Greek religion, Thesan is worshipped in the Etruscan religion. Her name appears on the mummy wrappings of the Zagreb mummy (Liber Linteus) and on a bronze tablet from Pyrgi.

Thesan was depicted on several bronze Etruscan mirror backs, bearing a great pair of wings on her back like many other Etruscan goddesses, especially appropriate to a sky-goddess. One meaning of her name is simply "dawn", and related words are thesi, meaning "illumination", and thesviti, "clear or famous". The other meaning of her name connects her with the ability to see the future, for thesan also means "divination", as seen in the related Etruscan word thesanthei, "divining", "illuminating", or "brilliant". This relates to her function as a dawn goddess – since divination throws light on the dark future and enables one to see what may happen, like the dawn, which illuminates what was previously dark. She was called by some as a childbirth goddess, as she was present at the beginning of the day, which finds its parallel in the beginning of a new baby's life. Similar to the Roman goddess Lucina, goddess of light and childbirth, who brought the infant into the light of day.

The Etruscans identified their Thesan with the Greek dawn goddess Eos. In the Greek legend, Aphrodite had found Eos in bed with her lover Ares; to punish Eos, Aphrodite "tormented with constant passion, and Eos became infamous for her many young lovers. The Etruscans seemed to quite like these stories and easily transferred them to their dawn goddess Thesan; the stories depicted on the mirrors are generally straight out of Greek myth. Thesan, the goddess of the dawn, “,” is depicted abducting a younger mortal on several engraved Etruscan mirrors dated from 530 to 450 B.C., w

The upper exergue has Thesan (Eos), the goddess of dawn, in her quadriga, a four-horse chariot. Asset number 812745001

A common representation of Thesan is carrying off Kephalos. The handsome hunter is the son of Hermes. Eos is often depicted carrying or embracing Kephalos before returning him to his wife, Prokris, in Athens.

The motif of Thesan and her lover can be found on Etruscan mirrors, pottery, and tomb frescoes.