AntaresScorpii) is a star. Its name derives from the Greek words meaning "similar to Ares" or "rival of Ares," probably due to the similarity of its reddish hue to the appearance of the planet Mars. This distinctive coloration has made the star an object of interest to many societies througout history, and many of the old Egyptian temples are oriented so that the light of Antares plays a role in the ceremonies performed there. Antares was one of the four "royal stars" of the Persians around 3000 BC, and some writers claim that it is the "lance star" referred to in the Biblical book of Job.

Antares is an M-class giant star, with a diameter of approximately 6.24 × 108 km, or slightly more than the distance as from Sun to Mars. It has a very low density.