The Aduatuci or Atuatuci are, according to Caesar, a Germanic tribe formed in east Belgium descended from the Cimbri and Teutones, who are tribes thought to have originated in the area of Denmark.

They are allowed to settle in the region by local tribes.

The Aduatuci send troops to assist the Nervii or Nervians in the Battle of the Sabis, but are too late, and are later defeated by the Romans after withdrawing to a fortified Aduatuci city.

After their defeat by Caesar they disappear from the written record, but their survivors possibly contributed to the later tribal grouping known as the Tungri in Roman imperial times.