List of octagonal buildings and structures

Octagon buildings and structures are characterized by an octagonal plan form, whether a perfect geometric octagon or a regular eight-sided polygon with approximately equal sides.

The oldest surviving octagon-shaped building is the Tower of the Winds in Athens, Greece, which was constructed circa 300 B.C.; the Pharos also had octagonal design elements but no longer stands. Octagon houses were popularized in the United States in the mid-19th century and there are too many to list here, see instead the list of octagon houses. There are also octagonal houses built in other times and cultures.

Below is a list of octagonal buildings and structures worldwide, excluding houses and windmills.