may refer to:
- Ostia Antica, a township and port of ancient Rome
- Ostia (town) , a modern township (also called Ostia Lido or Lido di Ostia) on the Tyrrhenian Sea coast, near Rome, Italy.
Usually, when modern Roman people say «Ostia» they refer to the modern town, not the nearby archaeological site.
It can also refer to either of two modern districts of Rome: