Santa Caterina da Siena a Via Giulia, Parish church in Via Giulia, Rome, Italy.

Santa Caterina da Siena a Via Giulia is a Baroque parish church on Via Giulia in Rome's Regola district. Its single nave has four side chapels and a slightly raised, apsed presbytery under a barrel vault. The vault panels hold two tempera paintings of music-making angels by Ermenegildo Costantini, and each wall carries four oval paintings.

The church was first built in 1526 to designs by Baldassarre Peruzzi, serving a Sienese confraternity that had settled in Rome. Repeated flooding from the Tiber caused serious damage, and it was fully rebuilt between 1766 and 1775 by architect Paolo Posi.

The facade carries sculptures of Romulus, Remus, and the she-wolf, pointing to the founding legend that links Siena to Rome. This stone detail makes visible a bond between the two cities that the Sienese community in Rome has long kept alive.

The church stands on Via Giulia, a straight street in the Regola district that runs parallel to the Tiber. The entrance is on Via Giulia, while the building extends through the block to Via di Monserrato, where the 1912 facade imitates the house of Saint Catherine in Siena. The archconfraternity's oratory on the first floor of the adjoining building holds the old church's surviving works.

A large fresco painted by Lorenzo Pecheux de Lyon in 1773 covers the apse and shows Pope Gregory XI returning to Rome from Avignon, where the papacy had been based for decades. This subject was chosen to honor the role Saint Catherine of Siena played in convincing the pope to make that return.