Aristarchus of Tegea was a 5th-century BCE tragic poet from Tegea in Arcadia. He was a contemporary of Sophocles and Euripides and wrote for Athenian dramatic festivals. According to the Suda lexicon, he lived to be 100 years old, authored 70 plays, and won two dramatic victories. The same source contains the improbable claim that he taught Sophocles.

Only one of his play titles is securely known: Achilles. The play itself is lost, but fragments survive, including a line concerning the "Tegean table" quoted by Athenaeus. The play likely treated episodes from the myth of Achilles. Aristarchus exemplifies the geographical spread of tragic composition beyond Athens during the Classical period. His reported longevity and productivity mark him as a notable figure. His fragmentary work is of primary interest to scholars studying non-Athenian tragedians and the remains of lost Greek drama.