Tantalus (Ancient Greek: Τάνταλος Tántalos) was a Greek mythological figure, most famous for his punishment in Tartarus: he was made to stand in a pool of water beneath a fruit tree with low branches, with the fruit ever eluding his grasp, and the water always receding before he could take a drink. He was also called Atys.

He was the father of Pelops, Niobe and Broteas, and was a son of Zeus and the nymph Plouto. Thus, like other heroes in Greek mythology such as Theseus (his great-great-grandson) and the Dioskouroi, Tantalus had both a hidden, divine parent and a mortal one.

The Greeks used the proverb "Tantalean punishment" (Ancient Greek: Ταντάλειοι τιμωρίαι: Tantáleioi timōríai) in reference to those who have good things but are not permitted to enjoy them. His name and punishment are also the source of the English word tantalize, meaning to torment with the sight of something desired but out of reach; tease by arousing expectations that are repeatedly disappointed.