Temple of Hercules Victor, Ancient Roman temple in Forum Boarium, Italy.

The Temple of Hercules Victor is a round tholos of Greek Pentelic marble in the Forum Boarium, Rome. Its circular cella, 14.8 m across, is ringed by twenty fluted Corinthian columns 10.66 m tall on a stepped base; the original architrave and roof are lost, and the present tile roof dates from 1996.

Built around 120 BC, the temple was commissioned by the wealthy Tiburtine merchant Marcus Octavius Herennius, who dedicated it to Hercules, patron of the oil traders' guild. The Greek architect Hermodoros of Salamis may have designed it. After a flood in 15 AD it was restored under Tiberius, and in 1132 it was consecrated as the church of Santo Stefano alle Carozze; Pope Innocent II, not Innocent III, made the dedication in 1140. In the 17th century it became Santa Maria del Sole.

The temple was dedicated to Hercules Olivarius, patron of the olive-oil merchants' guild, by the wealthy Tiburtine trader Marcus Octavius Herennius. Its round form imitates the lost Temple of Hercules Invictus built by Scipio Aemilianus in 142 BC. Consecrated as Santo Stefano delle Carrozze in 1132, it became Santa Maria del Sole in the 17th century after a Madonna image found near the Tiber emitted a ray of light.

The temple stands in the open square of Piazza Bocca della Verità, beside the Temple of Portunus and a short walk from the Tiber. A low iron fence and a strip of grass and shrubs keep visitors off the stepped base, so the structure is seen from the surrounding pavement rather than entered. The ground level around it was lowered between 1809 and 1810, which exposed more of the base and columns.

Ten of the twenty columns were replaced during repairs under Emperor Tiberius in the year 15 AD and are made of Luna marble rather than Greek stone. This restoration shows how Roman builders used local quarries to replace damaged parts.