Piazza della Repubblica is a semi-circular piazza in Rome, at the summit of the Viminal Hill, next to the Termini station. On it is to be found Santa Maria degli Angeli e dei Martiri. It is served by the Repubblica – Teatro dell'Opera Metro station. From the square starts one of the main streets of Rome, Via Nazionale.
The former name of the piazza, Piazza dell'Esedra, still very common today, originates in the large exedra of the baths of Diocletian, which gives the piazza its shape. The porticos around the piazza, built in 1887–98 by Gaetano Koch, were in memory of the ancient buildings on the same sites, while the basilica of Santa Maria degli Angeli e dei Martiri on the piazza is based on a wing of the baths.