The Roman theatre of Philippopolis (Latin: Theatrum Trimontense; Bulgarian: Пловдивски античен театър, Plovdivski antichen teatar) is one of the world's best-preserved ancient Roman theatres, located in the city center of modern Plovdiv, Bulgaria, once the ancient city of Philippopolis.

The cavea, the area in which people gathered, is hollowed out of a hill or slope, while the outer radian seats required structural support and solid retaining walls.

The upper part of the tiers is interrupted by narrow radial stairways, which divide the cavea into wedge-shaped sectors (kerkides).

An underground vaulted passage begins from the centre of the orchestra, goes under the stage building and leads out of the theatre.

Another vaulted passage, passing under the central bank of seats of the top tier, connects the cavea with the Three Hills area.

Whereas Greeks preferred the exercises of gymnasium and stadium, Roman interest in sport went to the events at the theatre and circus.

Thus, presumably, gladiatorial fights with animals were held in the theatre, as remains of safety facilities in front of the first row have been uncovered.

This caused a major archaeological excavation, including the removal of some 4.5 m of earth covering what was left hidden by the landslide.

The monument was restored using the original architectural elements to the greatest degree possible, strictly following the anastylosis technique.