The white marble Arch of Septimius Severus (Italian: Arco di Settimio Severo) at the northwest end of the Roman Forum is a triumphal arch dedicated in AD 203 to commemorate the Parthian victories of Emperor Septimius Severus and his two sons, Caracalla and Geta, in the two campaigns against the Parthians of 194/195 and 197-199.

After the death of Septimius Severus, his sons Caracalla and Geta were initially joint emperors. Caracalla had Geta assassinated in 212; Geta's memorials were destroyed and all images or mentions of him were removed from public buildings and monuments. Accordingly Geta's image and inscriptions referring to him were removed from the arch.

The arch was raised on a travertine base originally approached by steps from the Forum's ancient level. The central archway, spanned by a richly coffered semicircular vault, has lateral openings to each side archway, a feature copied in many Early Modern triumphal arches.

The three archways rest on piers, in front of which are detached composite columns on pedestals. Winged Victories are carved in relief in the spandrels. A staircase in the south pier leads to the top of the monument, on which were statues of the emperor and his two sons in a four-horse chariot (quadriga), accompanied by soldiers.