Actia (Ancient Greek: Ἄκτια) was a festival of Apollo Actius, celebrated at Nicopolis in Epirus, with wrestling, musical contests, horse racing, and sea battles. It was reestablished by Augustus, in commemoration of his victory over Mark Antony off Actium in 31 BC; that it was probably the revival of an ancient festival is suggested by the celebrated temple of Apollo at Actium, which is mentioned by Thucydides, and Strabo, and which was enlarged by Augustus. The games instituted by Augustus were celebrated every five years (πενταετηρίς, ludi quinquennales); they received the title of a sacred agon and were also called Olympia, and ranked next after the four great games of Greece.

Actia were also celebrated at the same time at Rome by the orders of the senate and were also celebrated in other parts of the Roman empire.