The Temple of Janus (Latin: aedes Jani), is a temple to the Roman god Janus in the Forum Holitorium, Rome. The temple was built by Gaius Duilius after the Roman victory at the battle of Mylae. Its position is defined as 'ad theatrum Marcelli', iuxta theatrum Marcelli, 1 and extra portam Carmentalem The day of dedication was the Portunalia, 17 August.
Augustus began a restoration of the temple, a project completed by his heir Tiberius in 17 AD. The re-dedication day of the structure was 18 October. According to Pliny the Elder, Augustus brought a statue of Janus, a work either of Scopas or Praxiteles, to be dedicated in this temple.