San Tommaso ai Cenci, Catholic church in Regola district, Rome, Italy.

San Tommaso ai Cenci is a church incorporated into the Cenci Palace near the Tiber in Rome's Regola district, with a side exit onto Piazza delle Cinque Scole. Its rectangular interior holds a main altar with a tondo of murra turchina, a rare blue iolite, the only known example in Rome. The first chapel on the left displays the Storie della Vergine by Sermoneta, dated 1585.

The site was once known as De Capite Molarum for its medieval location near functioning mills that ground grain. During the 15th century, the building was absorbed into the Cenci Palace complex as the city expanded and the area transformed.

The church was long the seat of the Romana Fraternitas, one of Rome's oldest guild associations, and was later linked to the Confraternita dei Vetturini, the carters' guild. Every year on 11 September that confraternity had a Mass celebrated here in memory of the torture of Beatrice and Giacomo Cenci. Between the two portals of the facade, the Cenci walled up the Roman funerary inscription of Marcus Cincius Theophilus because his name echoed their own.

The church can be reached through a side entrance that connects to Piazza delle Cinque Scole, a small route that is easy to miss if you do not know where to look. Prayer services happen regularly, though certain religious ceremonies like baptisms take place at another church nearby.

The main altar holds a roundel of murra turchina, a blue iolite stone described in the sources as the only one of its kind known in Rome. In the first chapel on the left hangs the Storie della Vergine by Sermoneta, dated 1585. Between the two portals of the facade, the Cenci walled up a Roman funerary inscription of Marcus Cincius Theophilus because the name echoed their own.