Armed militants damaged the main gate of the embassy with a rocket-propelled grenade, a diplomatic source said.
There were no reported casualties, and no group has claimed responsibility for the attack.
Libya's interim government has had limited success in establishing control of the country, and foreign officials are often targeted. There have been several diplomatic kidnappings in the past three months in Tripoli, the capital.
Militants abducted two Tunisian diplomats, still missing, in January.