Amarynceus (Gr. Template:Polytonic) was in Greek mythology a chief of the Eleans, and a son of Onesimachus or of Acetor. According to Hyginus, Amarynceus himself joined the expedition against Troy with nineteen ships. Homer, on the other hand, only mentions Amarynceus' son Diores (Amarynceides) as partaking in the Trojan War.
When Amarynceus died, his sons celebrated funeral games in his honor, in which Nestor took part. According to Pausanias, Amarynceus had been of great service to Augeas against Heracles, in return for which Augeas shared his throne with him.