The Temple of Janus (Latin: Aedes Iani) at the Forum Holitorium was a Roman temple dedicated to the god Janus, located between the Capitoline Hill and the Tiber River near the Circus Flaminius in the southern Campus Martius.

[2] During the early imperial period, Augustus began a restoration of the temple that was completed by his adopted heir Tiberius on 18 October AD 17.

[9][2] The temple is known to have stood near the Roman vegetable market (Forum Holitorium) "at" or "beside the Theatre of Marcellus" (ad[10] or iuxta theatrum Marcelli)[11][a] and "outside the Carmental Gate" (extra portam Carmentalem).

[14] There are known to have been three contiguous temples from the Late Republic on the west side of the Forum Holitorium in the area of the current church of San Nicola in Carcere.

The columns and capitals were made of marble as well, unlike the nearby Temple of Portunus which had a stucco covering.